We have to be careful talking about competing devices in device-specific threads, but I think I can safely say this much: I bought a second PoTV One after buying an Edge and have been using my two One's exclusively (when I'm not using my bigger vapes).
The PoTV dosing caps are definitely the way to go, tho I think HR sells them, too.
There's no micro-dosing specific accessory for the One, tho the aforementioned F2 stem
should work with it. You can also cut one of the concentrate pads in half with scissors in such a way that you have two thinner pads and stuff them inside the dosing capsules to fill some of the space for micro-dosing. I've done this with one of the capsules in this photo:
The Dynavap cooling stems that Sneaky Pete sells fit the accessory attachment quite well. The nippled one can be pretty discrete and the green spiral one offers awesome cooling. I also like to use Sneaky Pete's Scorpion cooler as a dry-air cooler with the WPA; works great!