Yep, had this issue when i put some Jamex recliners in my GT.
What i did was completely bastardise
a seat of FXGT seats. The seats are actually riveted on to the rails, well big cold rivet type things, so you are unable to unbolt the seat from the rails, you can only unbolt the cushion you sit on not hte back rest!
Anyway get a grinder and grind these rivets flat, then you need to pry the seat off the rail with a crowe bar, or big screw driver or something, this leaves just the rails (with brackets to bolt to floor obviously!!), I just made some brackets from some 2mm plate, although 3mm would be better, and welded these brackets on, drilled holes in the appropriate places and bolted all up!!! Easy!!