Welcome to the forum happyretiree2013. Your Sequoia has a tow rating of between 7000 and 7400 lbs depending on the model. You will be pushing it with the Jay Flight you are thinking about.
Check the stickies in the towing section of the forum.
Jay Flights are a little more heavy duty than White Hawks, however we are quite happy with ours. Have added a Fantastic Fan in bath, new faucet in bath, a digital thermostat, which keeps a much better control over the temperature and a Progressive EMS. (electrical management system)
2012 Toyota Tundra 5.7 Litre DoubleCab
6 speed, 4.30 Limited Slip, Tow Package
2013 Jayco White Hawk 27DSRL
2010 Jayco JayFlight 26BH sold
Yamaha EF2000is Generators (2)
1996 Honda CB750 Nighthawk