Tension on a longarm is not an exact science. Take your time. Test the tension. Breathe. Try a few different things and see what works.
When you say "fuzzies" on the back, do you mean it looks like an eyelash? Some good tension on the back
like this - - - - - - - - - - - - - - - - =
and then some lousy tension like this _|_|_|_|_|_|_
???
That is an issue on top when the stitches on the back are uneven. I would
1) rethread the machine
2) check the needle is in properly and perhaps turned a smidgin to the left
3) tighten the tensioner a bit
4) loosen the quilt sandwich a little
5) make sure the clamps on the sides are all holding the quilt evenly
6) check hoe high above the quilt the machine is setting-- it should be about the width of your hand, maybe an inch, so there is no drag
7) if you have a stitch regulator, turn it faster-- you may be sewing too fast for the speed setting!
Good luck and let us know how you do.