I do just as the gal who trained you suggested. I load the backing, roll it to either end, spray the visible part lightly with water and tighten the rollers, let it dry (usually), roll to the next area, repeat. The moment you tighten the roller bar the wrinkles completely disappear, and you aren't risking the distortion that you may get if you press too vigorously. It's so much quicker, and works great. It doesn't take much water, so not much drying time either. I understand that professional longarmers may not do this because it takes a little drying time, and they may not want to put water on the customer's quilt, even the back.