Ciao Firenze,
Everquest code is pretty old and may be picky sometimes ... first of all, choose a set of safe graphic settings.
Check the eqclient.ini:
VertexShaders=TRUE
TextureCache=FALSE
WindowedWidth=1024
WindowedHeight=768
WindowedMode=TRUE
Then try to set Wineskin this way:
right click on your wrapper > show content > double-click Wineskin.app
Set Screen Options > Override Settings > Rootles (windowed) + Virtual Desktop at 1024x768 + uncheck decorate windows
Advanced > Configuration > in the Windows Exe field enter /Program Files/Sony/EverQuest/eqgame.exe and in the Custom Commands field enter patchme
You can install the custom THF files with Wineskin itself using the Install Windows Software button or changing the Windows Exe field and then, once finished, re-entering the eqgame.exe path.
Use one of the latest WINE engines ... 1.3.3.7 or 1.4-rc2.
Also, take a look here:
WineHQ-Everquest
Project 1999 Mac
The Porting Team - Wineskin section
PS
I will not have the time to start playing THF in the next few days ... I hope I will be able to experiment a bit next weekend.