Youtube is a good resource for seeing how others set this up. Most say to get a longer length of fuel line, and put the tank to the side. As long as the petcock is higher than the inlet to the carbs, it'll work just fine.
I have also heard good things about the Morgan Carbtune. Sometimes you see them on EBay. Alternatively, you could find a MC garage that has one, and ask them how much they charge, or perhaps they could loan it to you for some money. Shoot, if the price is right, it may be worth it to have them do it. Saves time.
Luke M
(3 months without the Avenger...how much longer can I wait?)
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.