I'm simple, Riva 510 with carts. I bring two filled carts attached to two atomizers. Despite living in the sticks and having to drive at least 1 hour to get anywhere I have yet to run out while driving yet (and I regularly drive 2+ hours one way for work) I bring two to make sure that I have enough on the way home. I also usually bring the juice I am vaping in each cart with me so that I can refill if I want to vape the same thing on the way home.
As for holding it while I drive I either stick it between my knees, in my gearshift hand, or in my cleavage. I don't really have a problem finding the button, I usually pick it up and manage to get my thumb right on the button without trying.
As for holding it while I drive I either stick it between my knees, in my gearshift hand, or in my cleavage. I don't really have a problem finding the button, I usually pick it up and manage to get my thumb right on the button without trying.