Michael Schlink:
It IS "unconventional" but works quite well. I
Micheal, I don't think it's unconventional at alll to wear combinations for climate. Bare, for example, offers quite a few optons for layering including the 7mm fullsuit with either a 7mm hooded or 5 mm hoodless vest, or a 3 mm hooded undervest.
The Great Lakes might warm up by late summer (surface temp) but drop below the thermocline and you're right back to 50 degree water.
My last deep dive was during the fall, and surface temp was 60 degrees, at 100 feet is was a fair bit colder. My 7mm fullsuit could have had an exta layer and I wouldn;t have complained. (BTW I have a failry high resistance to cold...Just one of those things you develop when you spend many hours out in the cold hunting and ice fishing).
ppatrick,
Start with getting yourself a proper fitting 7mm full suit. (one with internal cuffs, Bare Artics are pretty good, come in a wide variety of sizes, (includig some odd sizes) and can be purchased at a very resonable price at divetank.com. [I'm a former customer not affiliate with them]).
Next decide on whether or not you plan on diving in April, May. October and November. If so, (other than going to a dry suit) you'll probably need a extra layer of some sort. Go up a size and get a 7mm hooded vest. For example, if you need a large full suit, go with an extra large hooded vest.
You won't feel consticted and will get your torso up to 14 mm protection AND get 7mm head coverage. Covering your head when diving in cold water is essential...even if a minimal 3mm beanie. I believe it's about 80% of heat loss occurs through the unprotected scalp.
If you like...wrap it up.
Cheers