feline fanatic

a 10ft frame will accommodate loading a 90" long quilt sideways.
Some LA have channel locks but you can improvise a channel lock with vice grips (the spring loaded kind). You put the grips on so the carriage that holds the machine head can't move front to back (sometimes referred to as the Y axis). You need at least two, one in front of the carriage and one behind but you may want 4 to be assured of a more secure "locking". Not sure if the rental place will allow you to do that though. They don't harm the rails or the machine as the grip part is usually rubber but they may be hesitant to let you do that. You would space your lines by advancing the quilt. To ensure 1/2" spacing you could check it with a ruler but once you have the head locked in place so it can't move front to back you don't need to use the ruler to quilt the lines. The vice grips are functional but not foolproof. You have to be very careful when you move the machine from right to left (or left to right) you don't inadvertently pull it towards you. For this to work your quilt needs to be perfectly square and needs to be loaded perfectly too. I don't know enough about computer guided machines to say if there is an E2E program that would just do straight lines.

Edited to add it wouldn't be that awful to quilt like this on your DSM with a walking foot but I would recommend switching directions with every line.