It all depends on what size longarm, and design. My longarm is 18" so I have to roll more often. I also have it set up in my house so can take breaks whenever I want, which is too often. I use Red Snappers to load and absolutely love them, I bought zippers but hadn't sewn them on yet when I discovered the Red Snappers, so will probably never use the zippers.
If I were renting a longarm I'm sure I could get a queen done in 4-6 hours.