I have a small 18350 copper mech mod that I pair with a low profile derringer RDA, and most of the builds I have made were near silent. I can't remember the mechs name but that doesn't really matter, I believe a previous forum member called Crustyfolker sent it to me with a few other bits as a gift as we got on well.
It was my stealth vape for a long time, I used to use it on long bus journeys, holding in the vapour for a few seconds so there was no clouds coming out.
Where it is an 18350 I had to build within a smaller cells amp limit/CDR, so the largest I went with wire was 28 gauge. If I remember I did 2MM ID coils with 28 gauge kanthal between 0.7-0.9 and it was great.
In fact, it made me dig it out to take a photo, now its time to charge some 18350's and get building!