I have just recently got back into caravanning, after a break of three years, my previous caravan was a twin axle Swift Conqueror 640 saloon Max weight 1500kg from memeory, towed by a Vw Touran Kerb weight with me in it 1725kg's . Which was around the 87% weight of car to caravan ratio. I towed this for two years, and took it to Spain twice.I now tow a Swift Challenger 530se which weighs in at 1300kg's fully laden,Still use the Touran.
My observations are as follows.The first outfit always felt stable, and I never experienced any snaking etc. However it was always at the back of my mind that this was a borderline tow in my mind, you will find many references to towing ratio's here and to be honest I felt that I was always kidding my self that it was'nt really relevant.
On a down hill run, with a cross wind, and an overtaking coach or panel van, slight road camber, the ratio will be very much at the forefront of your thoughts.
I now tow at 75% and although the outfit dose'nt feel any different, the peace of mind that the ratio is stacked in my favour makes me feel better.
This results in relaxed towing. The twin axle was also a ****** to move around, whether you jacked up the front or not.
Personally I will not go back to Twin axles.
Paul.