Sway is an interesting problem. I'm not sure having a heavy tow vehicle or a tow vehicle with an appropriate manufacturer's rating makes a real difference in a swaying adventure. As I mentioned I've seen people with sway who had heavy tongue weights and big tow vehicles.
The appropriate thing is to watch for low level swaying and do something about it before it becomes the dangerous variety occurs. If one sees a little sway stop the vehicle and address the loading issues. (I suspect that big sways are more often associated with high speeds.)
I agree with using the brake controller to stop sway.
On this forum and others I have sought people who've had a swaying accident. I have yet to find a single person. I have met two large trailer owners with appropriate tow vehicles who have totaled their trailers in swaying events. Neither person understood how it happened.
As to wheelbase, certainly longer is better but what is equally important is the distance from the ball to the center of the rear axle
. It is the ratio of the distance from ball to rear axle
to the length of the wheel base that is important.
As to using the trailer's brake controller to kill sway, every day that we hook up and start out I reach over and activate the brake controller to check the trailer brakes
and to insure that I can reach that lever without looking.
As well another factor is the stiffness of the tires
I will say that I get a number of PMs about our tow configuration. I never say simply "go for it" or the like. I always mention our total setup, including tire pressures, tongue weights and our approach to driving. I suggest for everyone trailer brakes
no matter the trailer size.
The magic of the information age, the Internet and this forum is the ability to share information, both fact and opinion. To not share my experience would be wrong.
As to carbon footprint, it never concerns me except for the cost of fuel and the effect of rising costs on the economy.
Safe travels, Carol, you seem like a very calm, Canadian person...