so you can only have 3 different types of models per seedmap? if so, can you have more than one seedmap attached to a level?
You can have three types per seedmap (but each type can be a list of different models [e.g. green=grass=[grass1.mdl, grass2.mdl, weed.mdl, ...]]).
You can create one automatic attached seedmap with the wizard, but you can add unlimited seedmaps manualy (you need to understand/extend the generated coding).