I've seen 8lb false dwarf Mini Rex, so depending on the lines I would consider using a non-dwarf MR buck. Even with dwarfed Mini Rex the growth rates can be decent, and they do have meaty bodies. Bigger is not always better, bigger means more food, more room, more urine, more feces. Best meat breed I've ever raised was Florida Whites, thrifty efficient and prolific, top weight is 6 lbs. Take into consideration how many people your going to feed, how many lbs of meat your going to produce, and if you even like rabbit meat. I've come to the realization that I prefer chicken.