Adding Subclasses

First, I'm using Smaug 1.4a.
Second, what I want to do is narrow it down to four classes. Strip them of most of the stats and instead have the player choose a subclass based on their class. Now I'm used to messing with rom source and all the class/race stuff are external and the code is confusing for me. Where do I start? What all needs editing? All that stuff.
Thank you in advance for any help.

P.S. I'm baaack.

After not getting any responces what so ever I switched back to rom, which I think is better anyway, and did it myself. I now have exactly what I wanted without having to find uot what I had to change in smaug. Maybe I'll release snippet when it's finished.