Propshafts - which one to fit?

I ve got a truly messed up 110. Its a 1984 chassis with an 1993 Tdi engine. A LT77 gearbox with non-original serial number and 1.6 transfer case which means that at 30mph I am in 5th gear.....

The propshafts are about to break and I need to replace them. But which one to fit? There are several different ones depending upon the chassis number but with my mix of components the chassis number has become irrelevent.

Here are my suggestions:-

FRC8390 for the front
FTC3905 for the rear

Is this workable?

regards

Paul

why not measure them and phone paddocks,craddocks, or whateverdocks?

30 mph in 5th gear?!? are you sure its not been in low range this entire time??

No - actually I never drive in low gear - even when offroading. I ve got a 1.6 transfer box which I think is not suitable for a TDi200 engine in terms of day to day use.

Can anyone help on the correct partnumber?