I've had trouble getting Crimson Sweets to get very large in my area...no where near their maximum potential. The few I do manage to get are on the small side (7-10 lbs tops) but taste pretty good.
Sugar Baby's, on the other hand, I've had quite a bit of success with. They grow to their full size and ripeness and taste great. The shorter growing seasons in my particular zone seem to prefer the smaller sized melons in my personal experience with them.
As to your specific question, the sugar baby melon plants will take up far less space than the crimson sweets and are more likely to reach their full potential, in my opinion.
