I did get all of my bits installed into the panel to check fit and had to trim one item, do a little filing and cut a anti-rotation key slot. Everything fits great.
Then I started to fit the fiberglass former to the firewall. The bottom has to be trimmed so the top of the former matches the top of the firewall. I trimmed to bottom, leaving the sides to be trimmed later. I'll explain why in another installment.
I also cut and fit the side L-brackets, drilled them and cleco'd them in place.