The 35.7 has a wheelbase / length ratio of 53%. This is marginal, minimally acceptable, but will still probably wander a bit. The 37.7 on the same chassis has a W/L ratio of just 50%. This is below standard, and will likely be squirrely as hell.
Builders will try to put as much box as possible on a smaller chassis because, frankly, its cheaper-- and it also immediately puts YOU into the market for aftermarket stabilizer systems.
Before you buy, check out the RV Consumer Group at www.rv.org
They rate individual models as to quality, safety, handling, etc. They go into great detail about wheelbase to length ratio, and its well worth learning this. Good Luck.