>>7338929You could also look into Smooth-On and some tolulene / NOVOCS.
Enlarging is basically soaking the mold until it expands, but you might be able to dial it in with shrinking some of the casts (depending on the proportion of solvent you can go from 5-20%), but work with casts not original parts because resin is solvent resistant.
https://www.youtube.com/watch?v=we0nOvtAMw4