Hello Joe,
Welcome to FISD.
I will stick to Andrew's advice if I were you (but you seems to be on-top of things, asking the right question before diving in).
I cannot say for a commission set of RS armor but I do troop in a set of self-built Sandtrooper. I say from my experience working on RS is they are a very tight fit for a specific body type (the "idea" in movie, 5'10" / 170 lbs -ish) and there is very little margin to work with if you are a larger individual.