In the 1.1 version I changed the EQUI_Templates.XML file and the EQUI_Animations.XML file to make the whole thing work. This gave all the windows in the game the new interface without having to edit the XML for each file.
The Inventory window *does* have doe for the weight value, it's just outside the display-able part of the window.
Since I mostly just hacked someone else's inventory window to get the one in Lothay 1.1 and I had plans for a version over-haul anyway, I never went back and fixed that.
I'm pretty sure that the 2.5 Player window will work with 1.1, but -- I haven't looked at the code in a few weeks, so there may be some "gotchas" if you do. Feel free to try it out.
Vitaee, You can feel free to post your mods to my UI if you like. I'm glad people like it.
~Lothay