I want to convert my MTB into an ebike for heavy cargo hauling in a hilly area

Hi all!

Just as the title says.

I found this video by Tom Stanton on youtube (https://www.youtube.com/watch?v=1pm1RtCuE3A) and I'm very inspired to try something similar. Only thing is I'd like to ask some questions about torque, and how to get the most of it.

My use case for my ebike will be as a heavy cargo hauler. I want to tow a bicycle micro camper (similar to this one - https://www.youtube.com/watch?v=mkyVdQmD0So), and I'm hoping that the full load will be around ~130 pounds (~60Kg). My city is Vancouver Canada, which is quite hilly in some areas, so I thought I'd prioritize an ebike with really good towing and hill climbing capacity.

I'm not concerned about speed in the slightest, only torque.

1. How does one measure real world torque on ebikes?
2. In Tom Stanton's video linked above, did he just essentially make a hub motor style ebike? The brushless motor he used is turning a pulley, which in turn drives the rear wheel, which is exactly what a normal hub motor does?
3. Also in the video, at 1:50, he talks about the pulley ratio, and how in his first design the pulley ratio was off, which resulted in poor torque, but high speed. He then makes the pulley bigger, which seems to inverse the results with higher torque but lower max speed. If his pulley was made even bigger, would that just keep growing the torque?

Like I said, I'd love to try something similar, but I'm no engineer and may just end up buying a regular ebike for my needs.

Thank you for reading