Hi Kirt,
I used a 1/4 inch thick maple rib doubler. I made a rib that looked like W-4Z and W-5Z. I think those are the part numbers. They are the rib doublers that face each other for rib W-4 and W-5. This will give you more wood to screw into, to mount the landing gear. Most people that I know use an air cylinder to operate the canopy. I believe the one for the P-51 is 4 inches long. I don't know who sells them. But I have seen them.

Karl