S3/4 Seat frame drawing/dimensions

[60plus2]

Has anyone done or have access to a drawing or dimensions of the elan S3/4 seat frame.
I have a 1970 plus 2S with reclining seats being 6'5" I struggle for room. I recently sat in an early plus 2 with the regular elan seats and found they give more leg room and are actualy lower than the recliners I have.
I want to fabricate some frames which I can retrim with the Newton Comercial covers.

[Bits]

Replace the seat with one out of an Elise - this will give you a couple of extra inches.

I have also bought a Tillett B5 carbon so I can wear a helmet for track days. Tho I have not bought the frame for it yet to find out how low it actually goes.