Good 4 pt seats

If you are putting in a cage, (or a bar) nhra rules mandate that the seatback has to be attached to the main hoop crossbar, and you will have to use a five point belt.
Choose your seat accordingly. In other words, a nice plush comfy seat likely will be difficult to tie to the rollbar. And it will likely need pass-throughs for the shoulder and crotch belts.
That's why you see Kirkys and one piece plastic seats like above in cars at the drags.