Boarding out a 90, a bench seat related question?

I'm going to board out the back of my 300Tdi 90 for a few reasons but am also wanting to re-install one of the rear bench seats, however how far back onto arch do the bench seats fit (I haven't yet got one) as I'm needing to know whether I can board straight down from the below the sky light to the arch, or have to work with the angle of the sides of the body to give the maximum width of the arch??? Any help would be appreciated, or a pick of someones who's done it allready even better!

In my previous 110 and in my current 90 there are bolt fittings for the seat backs just below the window line in the plastic frame. I took my windows out and panelled the area in aluminium - that's another story. Anyway, I am thinking that seats would fit within your boarded area going straight down from the window. Benches are shallow and not the most comfortable so take up less width within the rear cab anyway. Nobody can tuck their arse into the lower curved recess of the Defender, so I doubt anyone would bolt a seat back that far either ;-)

Jamseyboy, I did think that no one could fit there arse back there but wondered if the mountings for the benches fitted back into that space?