The latest Davides - both sizes - are easy to convert to use single bottom coils. Just take off the middle ring (that holds the coil) and the little white grommet that's up by the chimney. At that point, you can simply put in a single bottom coil, or swap the base out with the Kanger AFC base appropriate to the size, i.e. full or mini.
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Yes. I know.
The Davide dual head models
all have a two part assembly for the coil heads. There is a middle ring which is removed (along with the grommet) to convert to the Kanger/Evod coil. The bottom ring is what actually holds the coil itself. The grommet is fitted into the bottom of the tank center tube.
The original Davides didn't have any grommet at all because they only used the Kanger/Evod. I don't think there's any easy way to mod them so that they can use the Aspire. I suspect that if there is you'd end up buying enough extra pieces that you mind as well get a later model Davide. It probably wouldn't cost much more.
Some caveats. It was the first iteration of the dual head model which involved removing a tiny grommet from the bottom of the center tube when switching to the Aspire heads. Not that big a deal, except that you had to take the tank apart to get it out without fear of damage (which means that you had to empty the tank) and if you lost it then you couldn't change back. (I recently found one vendor that sold the grommets separately.)
I mention this because the last few gold finish I bought from Ebay were that older style. There wasn't any way to determine that from the write-up.
The newer iterations don't use the grommet. Far superior. No tiny plastic pieces to lose, and you can swap coil heads without having to open up (and thus empty) the tank. but I've only found those in gold finish a couple of times. I don't think they made a lot of them with that finish.
One disappointment I ran into was that the new style (dual coil head option) Mini Davides had a slightly smaller body diameter than the originals, so none of the outer tank components were interchangeable. A minor beef, I know, but I don't understand why they didn't just leave them the same. I don't think it would have affected their sales. I know
I would have bought the new ones anyhow.