I too have a Grace Pinnacle frame, and a Viking Mega Quilter..........I have difficulty with queen and king quilts (frame is set to 10 feet) due to limited throat space (10") n the machine.........I have heard wonderful things about many of the mid arm quilters, (Baily, Tin Lizzie, HQ16) and now Viking also has an 18" throat mid arm quilting machine....and they also sell a frame that is made by the Grace Company.........
There are several reasonable ones out there.....Have him do a little research on those included in responses from this blog.......