Ok. After Mondain's Legacy which UO expansion bumped the art tile limit from 0x3FFF to 0x7FFF and which one bumped it to 0xFFFF? I am thinking the bump to 0x7FFF came with High Seas but I'm not sure.

As regards the maximum skills at character creation, is that client or expansion related? And if it's expansion related does anyone have the max skills at creation numbers for the various expansions?

Ohoho...these questions are history-related I would say
Too much information about UO clients and their files is lost in history. Yukiko you're the perfect one to collect all these info and upload them somewhere

Yeah I might still have the HS client. I think that's the client that bumped us to 0x7FFF graphics tiles. As far the max skills that is not as important.