I divided the per block confirmable queries into three natural sections, iterating over each in full before moving to the next. This reduces page swapping between tables. I then applied concurrency to each of the loops, using C++17 concurrency constructs. This results in at least a 300% improvement in confirmability for the baseline machine of 32GiB/10threads, averaging about 3 blocks per second, but this is still unacceptably slow. It appears that it has also modestly sped up the max machine, which previously completed in 2.5hrs, though I haven't evaluated that fully.