I wrote down and sketched a bit on a Tilesheet Manager, some of the text is maybe not readable, I'll try to photoshop a realistic example tomorrow, that should be best I think. So far, this is what I've got. It could be a standalone window, but working with more than one window can be really bad for workflow (like Gimp, it's terrible).

I thought I should mention I will keep the sheet sizes at 512x512 px at most and some that are even less than that (for small trees for instance) but still follows the 32px grid, would that be a problem? It would waste space. Not sure how much sence I'm making right now. :/