The enforcement of what is being discussed here was my job up to retirement but I have been retired toooo long to remember all the legislation to give u advice. You should speak to MTO enforcement section for advice, you need an accurate weight of your load on trailer, trailer weight, power unit and max load carried on power unit to get the answer you want and need to be legal and safe.
I pulled 2 atv's on a 6.5x12 single axle trailer with a Tacoma and on each trip north I would stop at a MTO scale along the highway that was closed to weigh each one of my combination vehicles axles. The scale are on and if you look you will see the readings for your axle weights.
The problem is not pulling but it is stopping suddenly with a heavy load being pulled by a too small of a power unit and maybe no brakes on trailer.
I always stop each trip north at a scale even with my boat trailer just to make sure I am safe and legal.