I have been sitting in the new seat to further evaluate it for further adjustments. Right now the biggest concern is the rib support impinging on the latissimus dorsi when I try to turn the steering wheel. The upper corner of the rib support is all I need to adjust, because everything else is Big, Too Big. The seat is 14.5″ wide at the back of the seat pan and I can get a hand between the seat and my hips, thickness, not width. And I can get a finger between the rib support and myself about ½ up the support, but right at the top corner it like negative clearance when I simulate turning a steering wheel, like right under my armpit.
Secondary concern is the fact the seat is aluminum, and like all aluminum structures is subject to fractures from work-hardening. What that boils down to is “adjusting” the seat could cause a catastrophic structural failure in a wreck that could cause jagged pieces of aluminum to be exposed right under my heart. This can be prevented by annealing the metal. This requires heating the seat to a point well below melting but still pretty warm, the standard test being to take a wooden matchstick and rub it across the surface and see if it leaves a streak of carbon on the surface which Google says is 800 – 1000° F and can be done with a propane or butane torch but only just barely because of the heat required to raise aluminum to that temperature. Aluminum moves heat like mad away from the heated area, called high thermal conductivity, and also I think it has a high specific heat the amount of energy required to raise the temperature of the material. But anyway, if I am careful I can soften the aluminum enough to make the adjustments without damaging the seat.
And I have to get up early for an RPG session that starts at noon and requires catching a bus at 1030 to catch the other bus that leaves the station at 1100 and gets to the stop closest to the game about 1135 or so, and then it is a 0.65 mile (1 km) walk from the bus stop to the house where we play, which gives me about maybe 3 hours of sleep if I quit now and play solitaire until my brain shuts down from lack of use.