I cut out the seal flange.  Drew the layout per the plans and then drilled the 1/8" radius with a 1/4" bit and

band sawed the rest out then deburred with the belt sander.

Notice I rolled the top skin that covers the sub panel.  This made it much easier to handle and install.

There's a few ways to position and drill the mounting holes.  I suggest holding it aligned with the sub panel and

drilling each hole, cleco and drill the next hole.  It's important to have these very much the same since the forward

canopy skin will rest here soon.

Then I made the angles for the mounting of the instrument panel.