First off, congragulations on the new suit.
Item 1. when you get ready to dive, squeeze every single ounce of air out of that suit. Put your fingers in your neck seal, and squat down, then push your arms (at the elbows) together. You want to start the dive looking like a grape. THEN put on the bc and your weights, etc.
item 2. You are severely overweighted, but there's no way to do a weight check until you get all the air out of the suit and the bc. I'm 5'8", 215, and I use 22 with heavy jammies underneath. Do the weight check with a 500 psi tank, and all the air out of the suit and the bc, like you would in a wetsuit. Take a breath, and keep adding or subtracting weight till you are floatng eyeballs-deep.
Item 3. The poster who said you want to look like a raisin and not like a grape is spot-on. If you are weighted properly, then you will HAVE to use the suit for bouyancy because it will squeeze you so bad on descent you'll have to put air in to keep the twins from hitting your tonsils
Item 4. don't succumb to using the bc for bouyancy. That is not easier in the long run, and a bad idea IMHO. All you need to do for bouyancy in a drysuit is put a little air in or let it out to remain comfortable inside the suit. It's easy once you get the hang of it. it's almost mandatory once you're properly weighted.
Item 5. I assume you didn't take a drysuit class, based on the weighting and other things. I would either take the class, or find someone to dive with you who is very familiar with drysuit diving and will help you with these issues.
Item 6. No, you didn't hurt the seal. You were so inflated you "burped" when you moved your neck. You probably got a little wet, too. No big deal.
I would be interested to see how your next dives go, if you follow this advice. Please advise me in a PM or on this thread. Good Luck!!!!!
one more thing: leave the exhaust valve open. It never vents by itself if you're properly weighted, and someday you may need it open in a hurry. It's a little thing but you'll see good drysuit divers vent slightly quite often. If they're good you wouldn't be able to tell if you didn't see the bubbles come from their exhaust valve.