It's surprising how a potentially uncomfortable seat can be improved by a bit of leanback.
True for my pal's 29 roadster.
The seat is a bit beat-up, but with the backrest leaned back it works ok.
Good for a day of travel in fact . . . long as you get out and walk around every couple hours or so.

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I forgot to mention that the van seat in the A coupe tilts forward for access.

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Another seat that cuts down nicely is an S-10.
Saw one of these sectioned similar to the ChryCo seat above and it made for a nice fit in a 29 roadster.
The back tilts forward as well.
Not sure if the backrest was sectioned so as to lower the seat vertically - don't think so - but the backrest was the right height to go a little way back into the trunk area just under the cockpits rear rail when it was tilted to the driving position.
That's a little trick that gives additional legroom.
Brian's kinda stuck there with his RPU, but a thin backrest should work well.

I understand the Ranger bench seats work well when sectioned.
The backrest tilts on these from what I've been told.

The S10 seat I saw had no foam or upholstelry on it which made it easy to get a good idea of what was required.
The way the springs are oriented on the ChryCo van seat above makes for an easy section job.

Fwiw, you don't need a very thick backrest to make a comfortable seat.
As long as you have lumbar support, 3-4" is thick enough.