Have just watched the videos on loading a quilt on this frame and think this would drive me nuts.
https://www.youtube.com/watch?v=tUkDcZpWkKo&index=12&list=PL9AWSLDAL8sw1I0U7mCV8C5JwkYDp4DqZ
First you need to have a large area to sandwich the quilt - with pins, adhesive or hand basting - which is what you do now. You will probably need your backing to be at least 6" on the top side, to clamp to the back roller, unless you stitch it to a leader first (you need to be able to access the top edge of the quilt so must have extra 'leader' fabric).
Then, after quilting a section, you must undo it all, move the quilt along, and re-clamp.
Sorry, too much fussing for this little duck.
If space is not an issue, are you able to keep the machine and buy a new frame and accessories necessary to set up the Sweet 16? If that's an option it should not be so expensive.
I guess I'm lucky my garage houses my longarm and a 10' frame, but I would prefer what you have to this set-up, in fact I'm going to test out the Sweet16 sit-down next week.
Good luck with your decision