I can't see from your pics where the problem is. Is it the whole boat or just the keel? Often I have found, that it has to do with the stringers and/or gunwales not being exactly the same length. The boat will twist to compensate.

You might want to look at this link on "winding":

http://www.clcboats.com/shoptips/stitch_glue/checking_twist.html

8 degrees is not too big a deal. Maybe it's possible your drift to the right was caused by something else? Wind? Heeling? Your temporary skin? Expectations?

If it is the boat, then pics showing the problem might help someone come up with an answer.

Good luck! BTW, there's always a next boat, and they get better each time. Yours looks good!

Dave