Since I now have a lot of time to kill, I decided to remove the seats from the 4C and raise the front of the seat, bottom cushion.In the case of the seat bolts....I agree that lube should be very lightly used on the screw itself to do the test finger tight start. WD40 would be a good choice as it evaporates out. The big tip is do NOT use a socket wrench to start the screws. Use fingers only to start and ensure the screw is going in clean. Those are fine threads and there have been some reports of people forcing them and stripping the socket in the floor.
In my car the 6 screws that fasten the seat, too the seat rails were all in the bottom holes, so the seats were in the lowest position.
I left the rear screws in the bottom holes. Then placed the 2 center screws in the middle holes. And the 2 front screws in the upper holes. This leaves the rear seat bottom in the lowest position, and raises the front of the seat about 1 1/2".
Prior to this, the seats gave little support to the thighs and just felt flat and level. It felt like I was sitting "on" the seat. Now I am more ensconced in the seat. And it feels more like I am sitting "in" it. What you are doing with this adjustment is just tilting the whole seat back at a greater angle. You can now, if desired, recline the seat back to an even greater angle relative to the tub floor.
When the seat is moved to the most rearward position on the seat rails, you will lose about 3/4" of rearward movement. The very bottom of the seat back will now contact the carbon fiber tub. It is not really necessary. But I did attach a rubber pad onto the tub,where the seats make contact. Similar to the ones that ALFA places on the top portion of the seat backrest.
I am 5' 11" and never have the seat even close to the rear of the tub. For that, I would need to lengthen my legs about 5 or 6 inches. Have not yet, figured how to do that.