Hi.
The different resistance coils help if you don't have a VV, and you want to change the vape.
I'm not sure why Halo recommends the high coils for the VV. The regular 2.2 work fine. I guess if you had a juice you wanted really cold, you'd go high resistance, but on mine, 2.2 at the lowest stting is cold enough for me.
And for a given juice, you'd have to go higher volts to get the same vape with a higher ohm coil. No need for me; the 2.2 and the VV gives me from too cold, through the "sweet spot" to too hot, so my range is fine.
ps, and get a few replacement tips, and a second charger adaptor.