Putting it in the fuel filter?? Eh? where did that come from?? I'm just going for the old fashioned- bosh- in the filler neck approach!
BUT does it make any difference if you put it in an almost empty tank, then fill up, so leaving it sitting in the bottom of the tank, or other way round- fill up the tank with fuel, then add the forte (so it'll be mixing in from the top)?? Dilemma I know!?!