I'm trying to figure out how to get in good with our PMEL section at my current base so they can calibrate, or at least test my stuff. Ive got 2 older Crafstman USA made units. Have treated me well. Not sure I've really ever even used my 3/8s yet. They sat in the toolbox(at my dads) while I was living in Germany for 6 years.I have some old sockets welded to a strip of 1/8" plate that I can mount in my vise. Set your torque wrench and hang the appropriate weight off then end and see if it clicks/beeps. Test at a low, mid, and high setting. Test at a setting just above the weight to ensure it doesn't click/beep. Save $50/$125.
Best practices:
Always store your torque wrench with it set to the "zero" (or lowest) setting.
You "should" put your torque wrench on an immobile test fixture (i.e. sockets welded to a strip of 1/8" plate) before you use it and cycle it through a few clicks before you set it and torque something.
Everything else you said is exactly what is required of us. I can't turn in a torque wrench unless its at its lowest setting. Right at the checkout counter there are fixtures like you mention. Our operating instruction says cycle them 6 times at their highest torque setting. For larger wrenches(over about 75ft/lbs), cycle them at the setting they highest setting you will use them for that day, 6 times.