On a ego type pv you really should try 1.5ohm resistance atties or cartos. I would also suggest checking out some mods as you
batteries ARE going to fail at some point. Plus I have gotten much better performance out of say a Mad Vapes maxi roughstack.
It will run 3.7 with a 18650, 4.8 with a NIMH, you can stack two 3v batts, or two 3.7 batts. I pay about 5 or 6 bucks for the 18650s or the NIMH batts, they last all day. You can get the mod, several batts, charger, some atties, some cartos, and still be at about the 80$ range, Plus check out their juices 60ml for about 13 bucks. No I don't work there but I spend a lot there.
Just be careful... once you build your first mod you will never go back.