Yea lets use a bunch of pizza boxes, make a shit load of trash to make are hash with water that washes away a bunch of terps, way to go b-man, what a great idea or wait a minute it wasn't your idea. How about taking a bunch of unusable cannabis material tumbling it to make farmers grade hash and working from there...
Can't really wrap my mind around having stacks of pizza boxes about.
I'm not sure what I'm doing either. I am still experimenting myself. I don't want to add any VG/PG or anything, they all leave a nasty plastic taste. I've gone down that road before.
The cannabis derived terpenes (Blue River) are the recommended "solvent" but are no longer available online in the US. Not only that, but the cost is something like $75 per tank just for the terps.
I don't think it's a standard bottom coil, though it is similar in design. I haven't taken one apart yet. It does work, but loading it is a pain in the ass. It does preserve the taste better than the other two pens shown. I'm still playing with it.