Taking a new hotend into operation (cleaning, forming, etc)
I haven't done anything special to set up mine. But it's probably worth doing a general cleaning. I'd swab it off with alcohol, including running a q-tip or similar inside the fiber feed path. Then blow out the nozzle with compressed air to make sure it's clear.

You could measure the nozzle diameter by fitting fine drill bits in to see which is the largest one the passes through freely. Be sure to measure how much fiber your extruder really takes in when you ask it to extrude a certain length -- but that's about the extruder, not the hotend per se.

Finally, I'd check the insulation, if any. I got a couple hot ends that had big gaps in/around the insulation. I've found that "high-temperature gasket maker" is great for improving insulation (depends, of course, on the shape and design of the specific hot end.