Nice score, they have now increased to $31.99+shipping.
As for fuel filter placement, idk if there really is a best way but this is how I have mine, mounted with some highly engineered race-ties.
Some run it in front of the tower, typically the shorter the line the better, but over all, my line is not much longer than stock and it sorta shields the filter body from engine heat. The longer the line, the longer the truck can run upside down (and I like to jog rather than sprint

) With that said, some have almost entirely eliminated the half-tank lean condition by simply rotating the fuel inlet on the carb towards the tank and running a short direct line across the back of the carb to it. One could place a filter in that line as well.
I use these small Dubro filters that I added in bulk onto a Tower order awhile back.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFRL5
They would fit practically anywhere, and they have a handy little optional "in-line plug" that allows one to disconnect the line from the tank and loop it back to the plug to close the fuel system for storage or w/e. It also makes for a good mounting post.