George Aldrich's original FliteStreak plans show the CG just behind the leading edge log. I have seen a copy of his plans which have a CG placed over the spar. This CG has been mostly erased and noted "wrong CG" in George's hand writing. I would try your airplane with the CG close to the leading edge log, ie an inch or maybe a bit more back from front of the leading edge. If the airplane is not responsive enough to suit you then start adding tail weight. You may in fact be a little nose heavy.

I think your tank will probably work. It is going to want to go rich on you in flight so go ahead and lean the engine out. I'd do the first flight with not much fuel as you are just trying to get a base line to go from on the CG.

I'm building a Brodak kit FliteStreak which is an accurate replica of George's original airplane. I built a Topflite Streak long ago and recall it with fondness. No recollection as to where it balanced.

Jim