Yep.  A heat gun (or hair dryer), and Bob's your uncle.  You can unstick bad puzzle joints or scarf joints with heat, too, as long as not many days have passed.

  So I tried a hair dryer this morning.  It has bee about 30 hours and didnt seem to soften it at all.  I left it on high for 5-10 minutes and was able to feel the heat on the opposite side.  Is it likely set to long already or would I need higher hear like from a heat gun?

You should still be able to loosen seams at 30 hours.  Don't be afraid to get it bloody-well hot.  You're not going to damage the wood until you get to 450 degrees or something, way beyond what you can manage with a hair dryer.

Off by how much? You are in the middle of "Boat or Furniture" conundrum. I accidently broke off the last 3/4 of an inch of both of my shear panels on my SWS. They were too skinny to try to glue back on. After the kayak is finished, I am the only one that knows what happened. Even with a varnished boat, most likely no one but you will know. Good luck, JRC.