I went higher in nic at first and got confidence that I would get nic from it. But, it made me not vape as much per hour. But, I did get confidence. I would get a bottle of 24mg and several bottles of 18mg. Just to see where he is at and let him fall in where he is comfortable as to nic content. For ohms, I would stay between 1.0 and 2.0. There are a lot of directions to go in vaping, but that is a middle ground for a new vaper.
PG or VG?, I tend to about 70% PG. PG carries the flavor better, but, it doesn't create clouds as well as VG. It kind of depends what your/his desire is.
If you are doing factory coils, well they are a bit harder to clean and re-use. Homemade coils, on the other hand, are easier. Coil, and wick, can get "mucked" up with juices and that affects clean burning and flavor. I use rebuildable coils. I pull the messy wick out, light up the coil to burn off any residue and then insert a fresh piece of wick. To burn off any residue from juice, I raise the power about 5-8 watts. Coils do get "gunked" up. Pure cotton is fine, and there are other wick materials. Walmart cotton is fine.
I would do the maintenance/cleaning tasks with him. It is demonstration-style teaching.
Teaching one person at a time is only...one person at a time, but it is one more person that is no longer smoking.