Well, while I haven't followed your link you posted and obviously can't vouch for its quality I CAN say that in my experience, the pains of setting up Hammer or Quark or any of those Interior-making programs with all their hacky plugins and such is not worth it, even if you do have a british guy like me telling you how.
I much prefer Torque Constructor. Its free, intuitve and requires no hacky plugins, funky exporters or damn WAD files. Head over to
www.garagegames.com to get a copy. It works very similiar to Hammer and quark, perhaps easier and there is nothing to setup because it is designed around TGE (The base of BL).
Constructor is worth your time, hammer and quark are not.