I built my stab with the trailing edge laying flat on the table, and shimmed the leading edge accordingly for the centerline of it to line up with the centerline of the trailing edge. Then I put the ribs in and sanded the airfoil for the stab into it, then sheeted it. I sheeted my stab with 1/16th.
Attached is how I built the stab to my Staris, which was done the same way as the Thundergazer. Hope this helps