One of the items I notice some have struggled with on other build logs was to get the correct placement and fit between the engine mounts and the longerons. Seems the margin for error here is a bit tight. So as I typically try to do on parts, I marked out edge distance on all of the engine brackets first. Here I used an edge distance of about 0.025". It gives me a bit of a buffer rather than using the Mil-Spec minimum of 0.0219" (The buffer is always a good thing).
After marking things out. I placed the engine mounts to check fit (but not to drill just yet). Initially the fit is ok, its just on the line...
I've used some clamps to get things help in place. When I really look at it, it looks like things can get just a tiny bit better. There is still a small gap between the aft most flanges of the engine mount that I can tighten up. So I dug out another small clamp and clamped the mount vertically as well.
This snugged up the fit just a bit better and allowed for much more edge distance. Looking really good now. Plenty of material to work with on those mounts.