So, I'm wanting to download images using a mass booru downloader, I've got one set up and ready to go, but I don't want to overdo it and get shut down for taking up a ton of bandwidth.
Trying to archive some-odd 20k-30k images, and would like to know how often I should stop and take a break, or how fast/slow I should take things, unless I'm allowed to just blitz it and get it done with in one night haha.

Limit your API requests(requests to e621.net) to 1 per second. You do not need to limit your request rate to static1.e621.net, however please limit connection count to less than 10 connections in parallel. The latter restriction will improve your throughput anyways.