1) What is the best way to clean out the fuel tanks before first flight?  (I poured 2 gallons of 100LL in them and sloshed it around and drained it out the fuel drain but didn't seem to get all of it.)

2) I have the stock fuel system in my 360, which means the 2 wing tanks get pumped into the header tank via transfer pumps then the header feeds the engine. I have an Andair Gascolator installed between the Header and the boost pump to the engine.  

Should I use an Inline fuel filter if so where in the system and what type. 

Thanks

Bryan