If your system is an LP one, the most important thing is to have the least restriction possible from the buffer to the ram, that means the shortest, straightest and largest way possible, all the rest does not matter much. On a FW I would try to use 1/2" fittings if possible, couldn't manage on mine so I compromised with 3/8" fittings...results look encouraging!
Like Ed said, that tank is ok for a buffer, but surely not as a main.