Bob Woodhouse
Enthusiast
Frank Barba among others have some seat questions. Here is my experience:
On the drivers seat you will notice the seat does not face forward, it is pointed about 15 degrees outboard. This works but I prefer to be facing parallel with the axis of the car or slightly pointed inboard. If you remove and reinstall the driver seat you will find adjustment in the bracket to floor bolts that will allow you to reach at a minimum, parallel to the chassis centerline. Then get your best seating position with the floor to seat brackets using the bolts that attach to the seat. Once comfortable I found none of the other brackets, ie: the ones on the back and upper side near the window net, to be close at all. So the answer was to fabricate my own bracket for the backrest (photo if needed)then use lots of long bolts and shims to bring the side brace near the window net into position.
On the passenger seat, I ordered the large seat, then found you can't fit it in the car unless the fire-bottle is moved. So I unbolted the fire/battery tray and rotated in 90 degrees, not fun. Other solutions that don't come to mind right now should be considered. All of this is much easier if you are working on the car without the roof panel in place. As to mounating, I think the floor is adequate, you don't need to take the passenger as near to seeing God as you do yourself so the extra safety of a back brace should not be necessary. Also the roll cage is not designed to take a hit on that side with a passenger on board. So two sculptered angle iron in the fore-aft position gets the bracket mounts done, (photos if needed). Now for the belts. A 6 point I assume, you can dig the putty out of a number of the stock holes. I had to fabricate one floor anchor, that one uses the beam on the back side of the floor pan. Put a large washer on the back side. On the shoulder harness I went to the original SRT-10 bolt holes by cutting two small slits in the rear CC bulkhead. You may need to use a little fabrication of the brackets here. OK, put it all together, your done. Sorry about no pix. I don't know how to include them here.
On the drivers seat you will notice the seat does not face forward, it is pointed about 15 degrees outboard. This works but I prefer to be facing parallel with the axis of the car or slightly pointed inboard. If you remove and reinstall the driver seat you will find adjustment in the bracket to floor bolts that will allow you to reach at a minimum, parallel to the chassis centerline. Then get your best seating position with the floor to seat brackets using the bolts that attach to the seat. Once comfortable I found none of the other brackets, ie: the ones on the back and upper side near the window net, to be close at all. So the answer was to fabricate my own bracket for the backrest (photo if needed)then use lots of long bolts and shims to bring the side brace near the window net into position.
On the passenger seat, I ordered the large seat, then found you can't fit it in the car unless the fire-bottle is moved. So I unbolted the fire/battery tray and rotated in 90 degrees, not fun. Other solutions that don't come to mind right now should be considered. All of this is much easier if you are working on the car without the roof panel in place. As to mounating, I think the floor is adequate, you don't need to take the passenger as near to seeing God as you do yourself so the extra safety of a back brace should not be necessary. Also the roll cage is not designed to take a hit on that side with a passenger on board. So two sculptered angle iron in the fore-aft position gets the bracket mounts done, (photos if needed). Now for the belts. A 6 point I assume, you can dig the putty out of a number of the stock holes. I had to fabricate one floor anchor, that one uses the beam on the back side of the floor pan. Put a large washer on the back side. On the shoulder harness I went to the original SRT-10 bolt holes by cutting two small slits in the rear CC bulkhead. You may need to use a little fabrication of the brackets here. OK, put it all together, your done. Sorry about no pix. I don't know how to include them here.
Nice lawnmower you have in your avatar. 
