6" good, 7" not so much. We have a local "one lunger" race that allows for 6" of suspension travel MAX and one of the racers is interested in buying the rear suspension out of my parts sled to use in his race sled.
6 inches was a lot when that sled was new.
The limiter strap can be used to limit the travel to whatever you want.
Remember that suspension is for a 116 inch track. It can probably be mounted to work with a 121.
The limiter strap is the problem they are having now actually. They are using a ski-doo suspension with 10" of travel and using the limiter strap to get only 6" of travel. The team believes that this is working against them and causing a harsher ride.