I am prepared to be shot down in flames and retreat gracefully.
Don't worry, that only happens on the Flyer forum when one of the 6 self-appointed sky-gods deem a question too simple.
I was always told that the fullest tank would, in the event of fuel pump failure, give a better head of pressure than a lesser full one. I suppose I've just believed that ever since!! How that works in a low wing set-up is beyond me though.