I have an old HQ16 and cannot get behind it due to space restrictions. I visited a friend with the same machine and tried the pantos there. I took me twice as long as free from the front of the machine. All that lining up took time. That being said----look for the ones that have a bit more space in between the shapes....meaning not so dense.
Most people who quilt for money have lots of darling pantos for their clients to choose from. I am betting they are very fast at lining up each section.