Do you really need to know the excat torque for those lug nuts?

Based from my experience, hand torqued tightness will be enough especially for a light vehicle such as yours. Do not over torque by stepping on the wrench itself, you'll just have a hard time loosening it when the need arises. Lug nuts do tighten a bit more after being driven by few kilometers or so.

Btw, I also did used to have a smaller tube about a foot long to help tighten the lugs, I ended up with a loose threaded lug and some bent ones.