If its any consolation, the tank in my Escapade is as far aft from the firewall as it will go, around 1 inch. I use complicated plumbing to get to the carb (don't ask) and I have no issues with fuel feed simply because the back pressure is sufficient to always work with the vacuum in the crank case at bdc. It always draw fuel even in the vertical after 15min of flying (running on the wiff of an oil rag)