I completely understand the memory problem, I run a bot doing an absolute fraction of yours and it takes a good 30% though I haven't looked much into speeding it up because it comments regularly and since there is a limit of 1 comment/reply every so often (20 seconds) it just, I need it to be slow.
I do really like the idea (I thought I had upvoted before, guess not) and will definitely look forward to this to see its progression.