I have used both the rubber plug & the cord type plug. I prefer the cord type. I have never used these on anything other than passenger cars, pickups, or suvs.
My dad mounted a spare under his Journey between the frame forward of the rear axle. It is out of the way & easy access if he ever needs it. It is unounted. My Coachman has a mount behind the rear axle but I do not have a spare. When I change my tires out I intend to keep the best one as a spare. Even an old spare in good condition is better than a blown tire. I plan to only use it to get me to a shop where I can get a new replacement. As stated above, it may not be available in the local area where you have the blowout.
Dan Sees, Full Timing in the MH & Part timing in a S&B In Hampstead, NC
2013 Winnebago Journey 42e, 2014 Featherlite Car Hauler 3110 17.5', 2008 Mazda MX5,
2008 Toyota FJ Cruiser