It doesn't matter so much what the calivapers test said. Most of the drop is from the battery and secondarily from the cleanliness and smoothness of the contacting surfaces.
Im using an Aria Oros and a copper Manhattan the voltage drop is really low on those devices. The oros was tested on Calivapers with some really high tech machines and the drop was somethis crazy like less than >.01
im still torn between a regulated 150watts and dual 18650 series unprotected box mod.
On an unregulated mod, the only way to increase your wattage is to reduce your resistance. With a regulated mod, you are no longer limited to the battery voltage, so you can hit higher watts with higher resistance builds. This lets you increase the surface area and optimize the efficiency of your coils to get more vapour and flavour.
Even with an unregulated box wired in series? Bc then you can push 7.2-8.4 volts to your coil. which is more than what your going to get on a regulated device. Or am i Mistaken? which very well can be the case.
Im just worried that with an unregulated box in series, im going to have to start building with 28 gauge and higher bc ive heard that it will melt coils below a .6 or something like that.
The basic rule still applies to unregulated box mods with multiple batteries wired in series. To increase the wattage, you have to reduce the resistance. And to decrease the wattage you increase the resistance. That's just basic Ohm's Law. However you are correct in that you would have to build the coils very differently than you would with a single battery unregulated mod or an unregulated mod with batteries in parallel.