Here's some photos of my Gen 3 Coupe and mounting of the same Corbeau seats that you're mounting.
I'll give due credit to Edwardb / Paul Borror who also mounted these Corbeau seats in his Gen 3 Coupe and provided many insights in his Coupe's build thread. Paul provided exceedingly helpful directly overhead photos of his seat mounts laying in their final place on the chassis. I used and verified those with my own seats and mounts and then took my own photos of the seat mounts in their final placement in my car. I created (and inserted below) a 4-photo collage of the seat mounts in the car both with the sheet metal laying in place and without the sheet metal. One key aspect is determining how/where to bolt the seat mount to the chassis. I've used 4 bolts with three mounted to the under-seat steel floor and a 4th thru one of the chassis frame tubes. The bolt heads face towards the ground and they feed up thru floating nutserts that are mounted in the seat mount. that 4th nut must be drilled and mounted yourself. the others are OK as is in the seat mount.
Luckily, I was able to mount the driver's seat fairly straight in the chassis, with all aspects clearing the structure of the car. The top outside corner of the driver's seat headrest does make slight contact with the closest roll cage tube, but I affixed a small piece of Velcro (the fuzzy piece) to the tube with the fuzzy side against the seat vinyl. That should prevent wear and any squeaking. Regarding the passenger seat, it had to deal with a slightly different cabin structure and had to be mounted at a slight angle, but that shouldn't be too objectionable. Of course, I had to determine the thread size and lengths of the SS button head mounting bolts to be used. I also used a few hardened steel washers between the floor and seat mount to account for any gaps.
Look very closely for positioning and alignments, as well as Edwardb's helpful photos inside the seat mounts;
https://thefactoryfiveforum.com/atta...0&d=1567208523
https://thefactoryfiveforum.com/atta...2&d=1668924280
I believe that I did have to bend the outer seat belt attachment tab slightly outward to fully clear the seat.
My Coupe is at the painter right now, so I can't make any further checks or new photos.
I hope that helps.
Bob