The weight of the machine doesn't affect the bending of the poles. The weight of the quilt you've got rolled up on the take-up roller will make it bow but the square poles B-Line uses easily slip inside the round EMT conduit you can buy at any home improvement type store. I used my B-Line Studio model for many years at 10' & 12'. I used it with a 40 pound sewing machine on top of a 20+ pound PC Quilter and I had Max Throat which added another 5 pounds to each cross arm and the weights used by Max added another 6-12 pounds to the center support. I believe the HQ 16 weighs around 40 pounds so you'll be fine.
The only problem I ever had with my B-Line Studio frame was the unlevel, carpeted, concrete basement floor it was sitting on and then I only had issues after we went to 12'. It just refused to stay level and had to be re-adjusted after every quilt. The added stress of Max Throat made it "walk" a little. I had no problems before adding Max & I didn't have the bowing problem until I loaded an extra long twin that was heavy flannel front & back but that was easily fixed with the EMT conduit over the takeup roller.