Photo 1 is of the layout of the gear door location as best as I can determine it at this time.
Rails are 3/4" X 1" oak, and locating them for the Sierra gear was a real exercise as the photos show. There will be more structure on the right rail and I agree with you that there needs to be more structure between the formers on the left side.
Next post will show the modified gear in location as these photos were taken before the gear was modified.
One interesting point on the main gear doors is that the inboard door is larger, width wise, than the outboard door. Couple this with the follower door goes past the center line on its width, it makes for some heavy duty design and testing. Additionally, the nacelle diameter is wrong for the size of the cowl, and needs to be slightly increased to make it look right. The correct size for the cowl should be 8 " OD rather than the 9 1/8 " OD, so nacelle has to be enlarged. Not to criticize the plan but cowl is not scale, however, I am sure there was some really good reason for this, probably engine size. I have most of the new formers laid out and dry fitted, however (3 doors all different sizes, interesting).