I machine quilt large quilts on an old featherweight which has a small harp. I use spray basting as well as hand basting about 2 to 3 inches apart. It is absolutely critical to use a thin batting, like cotton. Warm & Natural or Hobbs are good. Poly batts tend to be fluffier, particularly the high loft battings. High loft is a nightmare to quilt by hand or machine. If you have chosen this and want to stick with it, I'd suggest tying the quilt.
I always start in the center and work in the lower right quadrant. You may wish to also baste sections with wash out basting thread before you begin your quilting. Good luck!