Tell me why you could not use the EC1112 along with a good one like RC 212 together in the expensive kits. That way you would be assured of complete fermentation and the good effects of the other yeast.
I'm not sure why you would want to tweak a high price kit. By spending that kind of money, I would not want to mess with what the experts at the kit manufacture have done to get it ready to make a good wine.