Welcome to the site!! It sounds like you still have rust in your tank. Buy this kit from Eastwood and seal it : http://www.eastwood.com/shopping/product/detailmain.jsp?itemID=382&itemType=PRODUCT&RS=1&keyword=tank+sealer .
"or attempt a mod I saw on here, capping all vents except the upper vent, and running that into the filler neck." I have done this, and it works great!
To answer your fuel filter question, I had a glass filter on a carbed car, it ran fine, but the filter was never full.