I agree with the suggestions regarding making a practice sandwiched piece and adjusting the tension as required but I have to say that apart from this I have always found it easiest to ensure that my sandwiched quilt is really tight to begin with (no wrinkles in it) and that the pins are no more than 4" apart.
Just my 2 cents worth on what works for me. Good Luck finding a solution which works for you
Maybe1day