Personally, I think the question between the two urethane bump stops is not the biggest difference in stability.
We have a C1920P 2007 Roadtrek on the Chevy and have done lots of testing of what works and what doesn't in improving handling, especially in wind.
Tops on the list of improvements is a rear sway bar. Hellwig makes one for Chevy, but there can be clearance issues if you have a generator right behind the rear axle. The rear bar will reduce understeer and improve steering response immensely.
The Chevy usually will be sitting right on the overload leaf on the rear axle. This leaf makes for very high spring rate and pitching on bumps and in wind, so getting the suspension off it is a good idea. Urethane booster may help, but air bags, which are adjustable usually do a better job, IMO.
For Chevies, IMO, the best thing you can do is get a big (1.375") rear swaybar in them, with some other method of getting up off the overload leafs. I think you would notice a huge change in handling, especially in the wind.
I am not a big fan of non adjustable urethane bump stops to try to replace actual suspension parts, unless there is no other option.
