Yeah, I posted the process about vertical rebuilds in the old coils in a separate thread where I reviewed the GS Air MS... no pics, though. With the new coils, vertical is pretty much the only option I can see since the chamber doesn't have a removable sleeve anymore. Insofar as benefits over a horizontal rebuild, I only noticed a slight increase in air flow and MAYBE a bit more flavor. In the old coils, 1.65mm was the inner coil diameter I used for a rebuild. The new ones look to be about the same... maybe closer to 2 mm if the coil stretched as I pulled it out.
With the new housing, it'll be more of a pain to rebuild, but ultimately worth it due to the larger juice channels. Looks like all that needs to be done is to pull the firing pin and grommet, remove the old coil (the whole wick unravels and comes with it), and rinse. Then build a vertical coil with lots of extra lead length. Wrap the wick around it a little tighter than normal until it just barely fits through the base, keeping the leads on opposite sides of the coil and covering them with the last layer or two of the wick. Insert this tightly packed bunch into the base hole, making sure the leads are NOT aligned with the juice channels. The wick should start to unravel slightly and fill the housing, all the way out to the walls. If not, take a pick and loosen it until it does. Reinstall the grommet and pin, trim the leads. That's it. In theory. You WILL need to effectively do it all twice though, if you plan to dry fire and test for hot spots, since wicking has to be done outside the housing.
Haven't gotten around to it yet, but I will soon.