Sounds like we are in the same boat. Since I am using an S-10 frame, I am removing the gas tank from under the seat. I am thinking of removing the under seat box as well and mounting the seats to the floor. I was sure hoping to use the space under the seat for fuse box and relays. But I don't think that will be possible now.
I may end up getting the bare frames and have the upholsterer build the seats.
I know the seat backs can't be very thick for the lack of leg room.
