How does it handle transactions coming in while it's running?
It's doesn't transfer them, but if both nodes are already connected to the bitcoin network, both will receive the new transactions. This program is intended to get old transactions to a node from another since they are not retransmitted normally by the bitcoin network. Anyway in a future, a ZMQ channel can be added to transfer them also. But be aware that it's difficult to get both mempools to be the same if there are conflicting txs with children. etc... among them (which is the normal thing by the way)
How does it handle a block being found while it's running?
The program retransmit a snapshot of a mempool. If a block arrives while running, the evicted txs wont be retransmitted or accepted by the nodes.
Any logic to check if to see if one node has more transactions then the other?
Yes, there is a summary at the beginning and at the end of the execution. But again, be aware it's almost impossible to get both mempools the same.
I have 4 nodes running on RPi and they are all dealing with the current bloated pool just fine with the stock setting but was thinking of increasing it to some stupid large size wonder if this would help by just bloating one and copying it to the others or will it not really matter.
It helps in the sense that you can shutdown one node, increase it's limits, reboot it again, and make a transfer of txs from another node to the rebooted one. The majority of the txs will be reloaded through mempool.dat file, but the program can transfer the txs that were lost while configuring the node. If any of those tx conflicts with mempool they will be rejected by the node.
