Combining a 5-4-3 suit with a shorty.

I bought a 5-4-3 Mares suit (5mm through most of it, 4 in the knee and elboy flex areas, 3 around the neck) about a week ago and am going diving off the coast this weekend. I was wondering if I get cold, would it make sense to waer a shorty (2-3mm) under it or would that just create a barrier between me and the real suit. I don't think the shorty would fit on the outside. Usually cold isn't a problem for me, but this early in the season is new territory.

Thanks

For what it's worth, here is what I would recommend. Look for a 1.5mm vest out of the "goldcore" type material. Wear this under your suit, next to your skin. This type of material ,at this thickness, will give you about the same amount of warmth as a 3mm vest that would be worn over your suit. Better yet, look for a vest that has a hood attached. This combination will give you the additional warmth without the problem of bulking you up.
Good luck and stay toasty warm!
Carolyn