The Rad Power videos do not show how to properly use a torque wrench. In fact, if you hold the torque wrench as many of the views show, you will overtorque the item. Here is a youtube video that shows how to use a torque wrench. There are many, I just picked this one. The key is, grip the torque wrench at the handle, not the body. https://www.youtube.com/watch?v=3v3hLvuO_KU
Very helpful link. Can you share from experience what size of a torque wrench is most useful on these bikes, or does one need all three as depicted in the video?
You only need a 1/4" for working on most things relevant to assembly of a RAD, larger ones will get in the way of many fasteners and the scales are usually higher. And pretty much every fastener you would touch would be 4 or 5mm, maybe a 6mm.
Harbor Freight has a sale right now - $11 for a 1/4" 20-200 in/lbs torque wrench. This is sufficient for most of the torque values on the RAD bikes. Use Google to search NM to inch pounds. They also have a 3/8" 5-80 ft/lbs for the same price.