I use 2ohm cartos on non-VV/VW
devices. On a VV/VW
device I don't really care what the resistance of the carto is, for obvious reasons.
I
have to punch my own cartos. The laser punched holes don't wick the 100% VG e-liquids that I use unless I thin them, which I only do with a couple of flavors. I had a couple of boxes of laser punched cartos, I carefully punched the same holes myself to widen them to fit my needs. I need 2 holes for the all VG liquids. I've been using a bullet piercing valve to punch the holes, but the tip is going to get dull pretty soon and there is no way to get a new piercing screw for it. Ray's cartopunch tool is quite the bargain, especially since it comes with an extra piercing screw. Like most punch tools (other than saddle valves) it surrounds the carto completely, so it shouldn't deform the carto much at all. I have one in my cart, waiting for midnight.
I tried using a Dremmel tool to cut a slot in a carto once. Even though I barely cut through the metal it tasted like metal and I had to toss that one. It can be done, plenty have pulled it off. If that's all you have on hand and really need a carto punched, give it a try.
My carto's holes are punched in the same place as the laser punched cartos, 2-3 mm above the bottom cap on the inside. I've never worried about getting the last few drops out of the tank. When the tank needs cleaning, I dump the last few drops into an atomizer or down the drain. A dead carto is a waste of e-liquid too, these things will happen.
and I am still trying out different flavors by using dripping . . . 
. . .VVV'ers . . . .
