The battery size doesn't in its self effect the vape. -- What it effects is how low you can build -- For argument, lets go with the purple Efest 10.5 amp 18350's... Amps = Volts/ohms --> Amps*ohms = Volts --> Ohms = volts/amps --> Ohms = 4.2/10.5 ==> 0.40ohms is the lowest build you can safely do under the continuous amp load on the 18350 purple 10.5 amp battery. That leaves no wiggle room so most people are comfortable building around about .45 just to have a safety margin. 4.2Volts at .40 Ohms = 44.1 Watts
Now lets do that same math with a sony 30 amp... Ohms = volts/amps --> Ohms = 4.2/30 ==> 0.14 Ohms and again that is with no wiggle room, so most people are comfortable building to about a .20 to have a safety margin. 4.2Volts at .14 Ohms = 126.0 Watts
Now the above numbers assume a lossless mod and atty and battery which don't exist... more accurate drain would be around about 70-80 watts on a sony and around about 20-25 watts on the efest 18350 after loss and all.
Now on the high end there is a whole lot more math that goes into this but this is the basic safe ranges. I tested out the purple efest 18350's and they held decent (even under pulse limiting which we wont get into right now) the run time was insanely low. Like 5 minutes or less. If you are not sub ohming more power to you with the 350's I miss the ultra stealth size... If you need more power... pretty much you need to step up to an 18650, you still can get some pretty compact mods... An example being a GP Paps with a Tobh and a shorty drip tip in 18650 mode is still pretty compact.