So I took some untimely away from project and came back with a fresh attitude.
I somehow figured out that I needed a little weight on the end of my rear corner belly pan.

I placed a small piece of a 4x4 on the belly pan end. It was like magic, the belly pan fell into place and showed me where to trim etc.
I'm in the figure it out the hard way mode and today's lesson is the 1/4 bolts I added to the c channel perimeter have to be installed upside from how I installed.This picture shows belly pan messed up from the bolts.

Next picture shows curbside corner before belly pan install with bolts in the correct direction to prevent any issues like I had with this side"
Oh well at least I have a usable pattern for attempt number 3 on this piece.
Practice makes perfect hopefully.