I removed the bottom skins after final drilling them and placed the Grove gear brackets in place and had to remove some metal from the bottom skins to allow for them to fit right.
The grove gear brackets are a little bigger than the standard Vans's gear brackets.
The skins were removed after final triming, deburred and then dimpled.
Pay close attention to the plans and the book. The forward hole of each of the two forward bottom skins is dimpled in the opposite of the rest of the #30 holes. This is for the rivet that will go through the angle that is attached to the firewall and I believe the cooling ramp will live there as well.
Onto scotchbrighting, cleaning and priming.
Also, make sure you roll the edge of the rear bottom skin where it meets the bottom skin and the centre section.
