Distance between D13 tubes is 627mm, so this tank will fit your Roadster.
As said above, it has a filler neck, a fuel out and a return, so that is the minimum. But it does not have an integrated swirl pot, so you will need a separated one if you go for fuel injection.
BUT, dimensions are small IMHO, the volume is only 21 litres. Even smaller than the one from the book (24 litres IIRC)!
I have a 34 litres tank from K4KEV (bigger volume than the one from the book, because he makes it taller). With my old 2.0i DOHC engine and a "sporty" driving (high rev, etc.), I consume about 12L/100km, so I barely make more than 250km with a full tank, in spite of its extended volume. Which means that with a 21 litres tank as the one you consider buying, I would have to go to the gas station every 150km, so I'm happy with a bigger tank
So, as said above, try to contact K4KEV on this forum. If you want, I can send you his personal email address by PM, just ask. I hope he is still doing fuel tanks though.
I got my fuel tank from him. IIRC, price was about £130 for this 34 litres tank, so pretty cheap. But it was 5 years ago... Kevin does a great work, the tank is baffled, it has an integrated swirl pot at the bottom, a filler neck, 2 in's on top (return, anti-roll valve, etc.), 1 out at the bottom (on the swirl pot). I have fuel injection, and I don't have an extra swirl pot, and never had fuel starvation problems with this tank. I asked him to put the filler neck and in's on the left side as I have a LHD Roadster.
Pictures of my tank on this page:
Hope that will help