I self RT as the last push on a picture, but I mean just single bumps on the next day or if you screwed up and posted on a dead hour. I also try to sometimes put process or interesting details from the picture, and that seems to help get some eyes on posts. After a few posts there's not as much return, for sure (and I had to unfollow someone who'd just constantly bump the same things or self repost several times in a week because most of the timeline was them), but it works for just a tiny push.
Artshare threads are great and helped me tons! Twitter shadowbanning people for RTing everyone in it, though, is not great. People said the best tip if you host one or try to push lots of people on it is to reply as much as you can so Twitter doesn't see it as spam, but not too sure about it.