Molicel makes good batteries. i've never used the P30B but their P26A has been used & preferred by many vapers for some time.
The general rule is to take the continuous discharge rate (CDR) X the # of batteries X 3 to get your max wattage. The P30B has a 30A CDR so you're good up to 180W in a 2-battery mod. It's good to not push it but you said you want just 70W, so you're fine.
What matters is the resistance whether mesh or 'normal' (they're called round wire) coils.
BatteryMooch, aka Mooch, is a vaping battery expert. It's always a good idea to find & read his reviews of batteries...
These tests below only note my personal opinion for the ESTIMATED ratings for the batteries I tested at the time I tested them. Any battery that is not a genuine Samsung, Sony, Murata, LG, Panasonic, Molicel, or Sanyo can change at any time! This...
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Always buy batteries from reputable battery vendors, please. 18650BatteryStore, LiIonWholesale, and Orbtronic are 3 well regarded online vendors.
Just fyi: It's generally recommended to get a good battery charger rather than recharging your batteries via the mod.
Good luck!