Thanks for all the advice and input. I ended up countersinking the flap hinge and adding a backing strip. I'm happy with the results.
RV-8 under construction as of Sep 30, 2012
Tail kit completed on Feb 8, 2012 (180 hrs)
Wing kit mostly completed, fuselage under construction as of March 6, 2014 (750 hrs)
Paid up for 2018