You are going to need a separate setup to test your recipes. The nano's or any clearomizer are designed to be used for any 3.5 - 3.7 volt battery, which we use universally in vaping. The coil resistance of the nano's are 2.4 ohm, so they aren't going to stress ANY battery. You could even put one on a cigalike battery, as long as the cigalike has a 510 connector. So I don't understand what you mean it wouldn't meet your needs well.
You're using a pod system for everyday vaping which uses replaceable pods exclusively. You won't be able to sample or test your flavors easily with any pod system. That's why I said you are going to need one setup to test flavors and another one to vape all day.
This is an honest question..
Those old old 650mah egos, are they 3.7v?
I know things like the old vision spinners are, and of course the new pen style batteries like the uwell whirl or the geekvape flint.
But I was thinking those little 4 dollar egos weren't that powerful?
I could always be wrong.. but it seems that non rebuildable dripper description states that it will stress those really old egos, but not things like the spinner..
this is the concern, to my understanding.