Regie wrote:id be checking what kind of weight is on the towball with the car backed on. Thats a whole lot of weight aft of the trailer axle
Adding to this, that is a single axle trailer. They are much more sensitive to stability issues than the twin axle variety, ask me how I know this. As a result, I would not tow a car on a single axle trailer at high speeds (once bitten, twice shy etc), towing round the burbs would be different.
Looks like you will be doing a fair bit of towing at freeway speeds: if you must use a single axle trailer, invest in as much stability control as you can, starting with electric brakes (if you haven't got them already), and use them to kill any wobble as soon as it appears by manually applying the trailer brakes.
If you add some aero to the car, specifically a big rear wing, either take it off for the tow, or re-calibrate your trailer stability at a specific AoA setting - I learnt that a rear wing works just as well on the trailer as on the track . Preferably take it off, as that obviates the problem of adjusting for headwinds/tailwinds, gusts etc. Sounds obvious, but I had to learn it the hard way, with massive instability of the towcar/trailer combination before I twigged.
I don't want to be a wet blanket, and I hope that you are already on top of these issues, but if not that is my 2c.
Good luck with the build, I'll follow progress with interest.