Fuel restrictor

OK. So I'm feeling kinda silly. Another user was kind enough to sell me his used/rebuilt fuel pump which is on the way because I can't seem to get mine to re-prime after an annual where the usual AD for replacing the gasket and filter screen applies. The new pump is on the way and the seller reminded me that the fuel restrictor fitting on it will need to be added. I had to admit my ignorance when I said that I thought the restrictor went on the line from the header to the wing tanks to prevent emptying of the header too quickly. The seller correctly reminded me that the restrictor fitting in fact goes on the pump to prevent over-zealous filling of the header tank and overflow out the filler neck onto the windshield. The restrictor fitting is available from Aircraft Spruce. The plane has flow just fine without all this time due to my ignorance.

So......I've seen plenty of folks talk about overflow from the header if the restrictor isn't used. I've not had that problem. And........this begs another question. What keeps the header from emptying too fast into the wings after it's full? I've noticed that if I'm grounded for a few days, the header bleeds slowly into the wings but it takes 10 days or so until the float gauge starts to indicate that the header is almost empty. What's keeping the fuel from heading straight to the wings from the header and emptying it more quickly after a flight?

Chris