I'm waiting for my seats to come back from the upholsterer, so I can't give you any solid measurements. I'd guess the front seats were around 18" deep(cushion to seat back). The back seats(inner facing) on mine aren't as deep. Maybe 15".
Here's the finished frames:
http://www.hotboatpics.com/pics/data...rames1-med.jpg
I'm going to take the finished seats and adjust them to what is comfortable for me to drive. I'll find the position on the driver's side, then mount the pass. side to match. Then I'll mount the throttle and place control to comfortable positions.
Hope that helps a little.