I need to find a prop shaft but need help choosing.

I have aquired a RWD KA shell buil by Imtec several yaers ago, it fell foul of the MSA rule changes and the project was abandoned as a result.

It however fits nicley in to an Autocross class here in France.

The shell has a 4x4 Sierra floor pan and is titted with a de-Dion rear end with Sierra diff, (lovely job). The mounting points for the prop centre bearing are all present and appear to be in the standard position. I have to asume the diff is located the usual positio fore and aft.

I intend to run it RWD only, I am fitting a Quaiffe Rocket box.

I am quite happy to cut and shut.

Questions are, please;

Are all sierra prop shafts the same in respect of length, centre bearing mounting and diff flange?

Could I use the Sierra Type 9 gearbox version?

I have seen a 2WD Cosworth one on the bay, but I know the spline will not fit my Rocket box, could I fit the yoke from an Escort/ Cortina ie is the UJ the same diameter etc?

Any advice would be most welcome, thanks for reading.