you probably wont find "updated" info on editing the UI.
There are instructions, along some some helper programs, on that site on editing the files. It has gotten a lot easier since they stopped editing the animation file all the time.
Your best bet is to find a file as close to what you want as possible, and see what they did with it compared to default/other files. Then tinker around with it yourself.
Remember that if your UI is to far out of whack, it will revert to the default ingame. And unfortunatly the best way to test UI is ingame, and it involves some time reloading the UI.
https://drive.google.com/drive/folders/0BxTGRVEV87-5SzIta09EQ3Y4Z1k
These are the ones I use. The player window has been modified from what EQInterface does with it. (will need the player.dds file to see it properly, has a fixed size)
The Target window is a build off the default, then modified to add things I wanted to display. It's size is adjustable.
I edited my CastSpellWnd to account for the additional gems. It is a modified version of one off of EQInterface that always shows spell labels, but doesn't have a background ( IE the text floats on transparent window). That would be the file you want to modify. (fixed size)
The buff windows files are small, but always list the buff, show the icon, and have duration counters, along with background tinting indicating buff/debuff/dot. They are adjustable in size, and the gems/labels are attached to the left hand side. So if for instance you wont want to see the slot labeling or timers, you can shrink the window and it will not show them.
View attachment 13545
That may be what you are looking for, or close. There is no "this is how you do it" answer that I can give. Only how I went about it, which is what I described above.