For the regulated mods and the NC in variable voltage mode it all depends on the wattage you intend to use. Use the link below to calculate your amp draw based on your wattage. Then select a battery with a CDR (continuous discharge rate) equal or greater than this value. I also included a link to Mooch's recommended battery list.
With the NC in VV mode, just
use ohms law to calculate your wattage.
Ohms Law - Calculating safe amp usage | E-Cigarette Forum
Mooch's Recommended Batteries | E-Cigarette Forum
Using a 0.07 ohm build on a mechanical mod is not only dangerous but pointless and highly ill-advised. If you want to use power levels that high you should use a multi battery mod to spread the load. There's literally no point in pushing a single battery mech that hard.
0.07 ohms is drawing 60 amps. As there is
no 18650 on the market with a CDR above 30 amps, you can see that that is a problem. Additionally most resistance meters are no where near accurate enough for dealing with resistances that close to a dead short. At resistances that low hundredths of a ohm make enormous differences in amp draw.
eg.
0.1 = 42 amps
0.07 = 60 amps
As you can see seven hundredths of an ohm less equated to an additional 18 amps. When most people use a 20 amp CDR cells you can see why this is ill advised.