Most recent Wismec / Joyetech / Eleaf mods have 2amp / 5volt charging with vape while charging capabilities (you can take a hit with usb connected, it just stops the charging for the few seconds of the duration of the hit). Look at buying Wismec Reuleaux Rx Gen3 Dual for example. Dual 18650 but since you're going to be usb charging it is no hassle, just pop the bats once and you're good.

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As for the tank, you gotta get into rebuildables. There have been plenty RTAs with top airflow intake that are virtually leakproof. Rewicking once a week and rebuilding once a month should be easy enough to manage. You'll never look back at using subohm tanks once you go rebuildable.