It's looking like the best seating alternative is going to be a foam covered plywood bench seat base, with the center rear cutout to fit around the driveshaft tunnel.
I've seen a number of recommendations for cutouts with webbing to make the seat a bit more butt friendly. What I've worked out in the old CAD system is a webbing cutout 11" wide, and 14" front to back. That is with 3" of two layers of 3/4" plywood surrounding the cutout.
Is that a big enough cutout to do any good? Is the 3" of wood surrounding sufficient? Too much? Not enough?
Now comes a biggie...I am going to have to put some kind of elements barrier (probably a sheet of aluminum) on the bottom side of the seat plywood, because there will be no floor under the seat at least on the driver side. The brake booster and master will be in that space. Approximately how much sag in the webbing can be expected when sat on? If more than about 1-1/4", I'm going to have to come up with another plan.
I've seen a number of recommendations for cutouts with webbing to make the seat a bit more butt friendly. What I've worked out in the old CAD system is a webbing cutout 11" wide, and 14" front to back. That is with 3" of two layers of 3/4" plywood surrounding the cutout.
Is that a big enough cutout to do any good? Is the 3" of wood surrounding sufficient? Too much? Not enough?
Now comes a biggie...I am going to have to put some kind of elements barrier (probably a sheet of aluminum) on the bottom side of the seat plywood, because there will be no floor under the seat at least on the driver side. The brake booster and master will be in that space. Approximately how much sag in the webbing can be expected when sat on? If more than about 1-1/4", I'm going to have to come up with another plan.