The GAV should be about 1 turn open or so when cold less when warm, some can run with it almost closed once the car is warm. If the gas runs out of the back of the carb, that is typically caused by 4 things. 1) float level too high (this is adjusted by placing more gaskets under the float valve). 2) stuck/sticking float valve, some of the new replacements have issues, try a higher end one from any of the model A parts distributors. 3) dirt getting into float valve, make sure your gas tank and lines are clean. 4) Float problems, a leaky float (solder or replace), sticky or bent float pin (clean up and / or replace), or float or float mount bent so float drags on side of carb bowl (straighten / replace).