I believe full credit for this goes to Ganlarg - I have not tried it but saved the article.....
Places to start:
In your EverquestLP/games/uifiles directory, you'll see a "default" directory. That contains the file for the default UI.
cmd-click on the defalt directory, then select "Duplicate" to duplicate it. Rename the copy to whatever you want, for example: "myUI". You always need to work with a copy of the default folder, otherwise the patch program will overwrite your changes when you load EQ the next time.
At the sites above, you'll find lots of custom interface elements. In most cases, you should be able to unload them, and copy the files into your "myUI" directory. The custom files will overwrite files in the "myUI" directory. Thats OK, its replacing the default ones.
You can then go into the game, and type "/loadskin myUI" to see if your new UI looks the way you expect it to.
In most cases, this should work, and you should be good to go. In some cases though, you'll get an error. This is usually due to an incompatability between EQPC and EQMAC. In order to get it working, you'll have to edit the XML files.
That isn't something I can give a direct step-by-step guide to. Basically, you want to remove references to:
1) The charm slot.
2) The "dyes" or "tinting" button.
For example, in tking's EQUI_Inventory.xml file, I had to erase the:
sections before it would work. I didn't have a problem with any other interface elements I tried.