the thing that i don't find or i like about the modles is that you have to modify all the stats if you whant to get them right. I know its all in the fun of making the map yours, but there should be a suggested model listed for each model thats on this site.
indeed, you should just experiment a bit, though some of the model discritions include an advized modelsize and there are lots of tutorials for more complicated spells. The rest you have to find out for yourself.