RE: Dimension Pro (how many parts?)
You can run more than one instance of Dimension - so as many instruments as you computer can handle.
As far as midi channels - there is a multi-timbral mode that assigns DP to channels 1-4. There are work arounds to this, I'm sure, such as freezing synths, but I've never used it.
hope this helps.
there came forth little children out of the city, and mocked him, and said unto him, Go up, thou bald head; go up, thou bald head.
24 And he turned back, and looked on them, and cursed them in the name of the Lord. And there came forth two she bears out of the wood, and tare forty and two children of them.