Seats Fixed or Not?

[Not Anumber]

No just straightforward runners. It would be simple enough to use spacers and longer bolts to change the angle between the floor and the seat.
What i'm looking to do is to change the actual angle between the seat base and seat back- trying to find out here if anyone has been able to modify these seats by taking the cover off and moving a couple of bolts, cutting out the fixed joint and welding in an adjuster mechanism, bending the angle with a large bar etc ?