batter

Ok so I really need some help, I currently have the smok alien 220w with two lg hg2 batteries. I ordered the dead rabbit rda with some pre built coils and some wire , what would be the ohm range I can go from or am I safe no matter what

I got a BecPro 50w by Smok but the power keeps reducing from a set 43watts to 38 and lower. Im currently using 3.7v 2500mah batteries but think it's time to upgrade. What would be THE Best 18650 to choose for 50w mods? One guy says " up to 75 watts or so a HG2 should be fine. 30 Q or VTC6...