Two thoughts on weight ratings and towing. If the factory says that the axle is rated for X amount, CGVWR is X, and you decide that based on Internet postings to exceed this and you have an accident (even if you aren't at fault), this MAY happen to you:
State brings in vehicle manufacturer engineer who testifies that the vehicle was rated for this amount of weight. You went over it. The axle was rated for this amount of weight, and you went over it. Then the engineer is asked about brakes and he says that the brakes are designed with a 20% safety factor which is not used in the published weight ratings. You were right at this. State then shows that your truck/trailer combination was over CGVWR. Where does that leave you?
A lot of posters will now yell and scream that they have towed such and such for years without a problem. Sure, they have gotten away with it. Maybe they will continue to maybe not. But with attorneys looking for someone to sue and collect from, do you want to be in the spotlight?
Read some of the NTSB reports on highway accidents. See what kind of detail they go into. I am not saying that the NTSB will investigate every accident involving an RV. What I am saying is that there are a lot of other sharp LE officers who know the same. Is it worth it?