Your comment about "hurry it up" tactics brought back unpleasant memories. It just isn't worth rushing any part of the building process, because you're more likely to screw something up. Then you'll have to spend more time to fix than it would have taken to do the job right the first time AND the fix will probably exact a weight penalty. (Dookie schmutz, anyone?)

I have built one boat and wish I hadn't rushed some of the early things. They all HAD to be fixed, which took more time (and money), added weight, and usually detracted from aesthetics as well. Fortunately, I did learn as I went along, but the ripple-down effect of early mistakes just could not be erased completely.

So my kayak weighed in at 52 lbs when I estimate that it should have been around 46 lbs with double glass layers on hull exterior and full interior glass AND seam taping. In my case, it was mainly epoxy overkill in the interior. By the time I did the exterior, I'd learned my lesson and that went well.

Don't judge weight by amount of epoxy used alone. I must've gone through at least 3.5 gallons--the kit came with 3 gals and I had to buy more as I went along. A huge amount of it got thrown out due to "going off" too quickly, drips, or just plain making too large a batch for the job. Again, these mistakes occurred mainly in the early stages, but they wasted a lot of epoxy.

Watch those end pours, too. It's easy to add a lot of unnecessary weight there. (Now, how did I know that?)