Personally, My sweet spot is "Low Resistance" at between 1.5 and 1.8 ohms at between 7 and 8 watts...
Sometimes when building coils for my AGA-T I wind up with what looks like a perfect coil, but it measures 0.7 to 1.1 ohms.
Technically I would consider anything that is at 1.2 ohms or less (i.e., won't fire on most vv/vw APVs) as a sub-ohm coil.
However, if I can out it on a mechanical mod with a fresh IMR battery (the eFest 2000 mah are also rated at 10 amps continuous draw BTW) and work out the hot spots, I'd just as soon go ahead and vape it, rather than go through the hassle of building another coil...
That said, my preference runts to flavor and throat hit, and less vapor. Thus, most of my juice runs around 70% to 80% PG
I don't drill out the air holes of my RBAs or RDAs because I prefer a tighter rather than airy draw...
It all comes down to preference... Which has been said many, many, MANY times in this thread.
Apparently Necessary Disclaimer: The item(s), and/or vendor(s) mentioned above, were purchased/patronized for my personal use, and in no way sold by or affiliated with my business interests...