Cut a trial piece of sheet metal approximately 12" x 4" to use as a trial fit to determine the dimension of the fairing fit with the stabilator installation. Marked up the trial piece with a marker, clamped in a vise, and heated the work piece with a propane torch until the marks changed color to remove the temper in the 6061-T6 metal. Bent one end past 90 with a hand brake. Set the piece in place to find the bend location on opposite side.
The bend angles on the trial piece were eyeballed to the shape of the opening. The HF handbrake produced a greater radius bend than had I used the HF bench mounted brake.
Forming the sheetmetal by hand to shape was much easier than standard T6 treated.