I've got a foot in both worlds, I have an IT education but have worked in or around skilled labor most of my adult life. Part of my current job even deals with training and evaluating people doing skilled labor.
In my experience, two kinds of people tend to do well enough to be described as thriving. Those who've worked with their hands before, either professionally or as a hobby, and those who approach the job with some humility and a mindset of wanting to learn and perfect a craft, similar to many artists.
It doesn't matter what your background is, white collar, blue collar, no collar, if you're overconfident and think a trade is going to be easy because you don't respect the mental and the physical aspects of the job, you're going to have a bad time.
Excluding a few examples like frequently used gym weights, common fastener sizes, and short distances, I still have to do rough conversions in my head to have an idea of what a metric measurement is, so I guess I'd say imperial.
But I wouldn't be upset if the US converted to metric.