If my math is right, 7m trailer, 1m hanging off the back, that makes 8m. that leaves 5 m projecting over the vehicle. That will bounce so bad with every bump that you will probably damage your roof and mast. You will be supporting only 60% of the mast on the trailer
You wont be able to cradle
or strap to the tow vehicle because as cheechako mentioned the car and trailer turn independent of each other.
In terms of legality here in alberta you can project
no more than 4 feet past your lights. Contact local transportation department for any country you are going through.
I haul trailers more often than not and would strongly recommend either a bigger trailer, flat deck
if possible, or contract
it to a shipping
company. If you aren't in a rush, you can usually get a decent deal when they need to fill a partial load.