Pre-MBA Fund Size for Post-MBA Large-Cap

I know that getting pre-MBA PE experience is the best path to jump back into PE after MBA. How difficult is to to go from MM PE pre-MBA to UMM/MF post-MBA? 

Also, is there a general guidance on the differences between MM and UMM in terms of fund size/AUM/check size? With firms raising bigger and bigger funds, it's becoming harder to distinguish the two what was once UMM/MF territory has come down to traditional MM/UMM space.