One mod I am making...
I had assembled the entire frame by itself and noticed the right mandible was not quite solid as the left. It felt this was because the left mandible has side framing immediately to each side of it. The right one only has a side plate on one side (the cockpit tube is on the other side of it).
I also felt the back ends of the mandible were 'mushy' with no support on that side, which didn't help.
So, in my case, I bought another issue 78 that contains two of the shorter mandible side frames, but you could scratch something.
My plan is to tack these across the back side just inside the mounting tabs of the mandible to stiffen it up.
I think it will help.