Not only because of that, but also because some CPU miners may include non-standard transactions, and you may be interested in collecting fees from them (especially if someone will put a standard transaction with tasty fees, as a CPFP of some non-standard transaction with zero fees). Of course, you can always just mine an empty block on the proper height, and don't care about fees, but I assume you want to confirm things, which were previously confirmed. So, if block 123,456 is confirmed, and you want to reorg everything from block 123,457 forward, then you should collect everything from CPU blocks, and put into your mempool (which "invalidateblock" does, but it also disconnects you from honest nodes, because then they don't see the same chain tip as you want to work with). And then, if you have your regular mempool, and all transactions confirmed by CPUs, then it should give you the maximum possible coinbase reward. In the current consensus, you cannot ignore CPU-mined blocks, but you can reorg them with a single ASIC block (because if ASIC difficulty is 1,000,000, then you can reorg up to 1,000,000 CPU-mined blocks in a single shot). But yes, the current plan from the mailing list is to hard-fork the network to the state, where mining blocks with CPU difficulty will be blocked. Which is equivalent to just releasing testnet5 with new rules, and with premine of all current testnet4 blocks. This is hard-fork. But it is quite likely, that there will be no CPU-mined blocks in this case, or they will occur very rarely. You can explore the mainnet chain, and count all instances, where the time between blocks was bigger than 3 hours, to estimate, how many such cases we could have in your testnet.
Not only because of that, but also because some CPU miners may include non-standard transactions, and you may be interested in collecting fees from them (especially if someone will put a standard transaction with tasty fees, as a CPFP of some non-standard transaction with zero fees). Of course, you can always just mine an empty block on the proper height, and don't care about fees, but I assume you want to confirm things, which were previously confirmed. So, if block 123,456 is confirmed, and you want to reorg everything from block 123,457 forward, then you should collect everything from CPU blocks, and put into your mempool (which "invalidateblock" does, but it also disconnects you from honest nodes, because then they don't see the same chain tip as you want to work with). And then, if you have your regular mempool, and all transactions confirmed by CPUs, then it should give you the maximum possible coinbase reward. In the current consensus, you cannot ignore CPU-mined blocks, but you can reorg them with a single ASIC block (because if ASIC difficulty is 1,000,000, then you can reorg up to 1,000,000 CPU-mined blocks in a single shot). But yes, the current plan from the mailing list is to hard-fork the network to the state, where mining blocks with CPU difficulty will be blocked. Which is equivalent to just releasing testnet5 with new rules, and with premine of all current testnet4 blocks. This is hard-fork. But it is quite likely, that there will be no CPU-mined blocks in this case, or they will occur very rarely. You can explore the mainnet chain, and count all instances, where the time between blocks was bigger than 3 hours, to estimate, how many such cases we could have in your testnet.

Not only because of that, but also because some CPU miners may include non-standard transactions, and you may be interested in collecting fees from them (especially if someone will put a standard transaction with tasty fees, as a CPFP of some non-standard transaction with zero fees). Of course, you can always just mine an empty block on the proper height, and don't care about fees, but I assume you want to confirm things, which were previously confirmed. So, if block 123,456 is confirmed, and you want to reorg everything from block 123,457 forward, then you should collect everything from CPU blocks, and put into your mempool (which "invalidateblock" does, but it also disconnects you from honest nodes, because then they don't see the same chain tip as you want to work with). And then, if you have your regular mempool, and all transactions confirmed by CPUs, then it should give you the maximum possible coinbase reward. In the current consensus, you cannot ignore CPU-mined blocks, but you can reorg them with a single ASIC block (because if ASIC difficulty is 1,000,000, then you can reorg up to 1,000,000 CPU-mined blocks in a single shot). But yes, the current plan from the mailing list is to hard-fork the network to the state, where mining blocks with CPU difficulty will be blocked. Which is equivalent to just releasing testnet5 with new rules, and with premine of all current testnet4 blocks. This is hard-fork. But it is quite likely, that there will be no CPU-mined blocks in this case, or they will occur very rarely. You can explore the mainnet chain, and count all instances, where the time between blocks was bigger than 3 hours, to estimate, how many such cases we could have in your testnet.

Not only because of that, but also because some CPU miners may include non-standard transactions, and you may be interested in collecting fees from them (especially if someone will put a standard transaction with tasty fees, as a CPFP of some non-standard transaction with zero fees). Of course, you can always just mine an empty block on the proper height, and don't care about fees, but I assume you want to confirm things, which were previously confirmed. So, if block 123,456 is confirmed, and you want to reorg everything from block 123,457 forward, then you should collect everything from CPU blocks, and put into your mempool (which "invalidateblock" does, but it also disconnects you from honest nodes, because then they don't see the same chain tip as you want to work with). And then, if you have your regular mempool, and all transactions confirmed by CPUs, then it should give you the maximum possible coinbase reward. In the current consensus, you cannot ignore CPU-mined blocks, but you can reorg them with a single ASIC block (because if ASIC difficulty is 1,000,000, then you can reorg up to 1,000,000 CPU-mined blocks in a single shot). But yes, the current plan from the mailing list is to hard-fork the network to the state, where mining blocks with CPU difficulty will be blocked. Which is equivalent to just releasing testnet5 with new rules, and with premine of all current testnet4 blocks. This is hard-fork. But it is quite likely, that there will be no CPU-mined blocks in this case, or they will occur very rarely. You can explore the mainnet chain, and count all instances, where the time between blocks was bigger than 3 hours, to estimate, how many such cases we could have in your testnet.