I would definitely consider this atty at 22 mm and 2 ml, and I agree there may be an extension down the line. When I had mine briefly (waiting on a different color now) I actually enjoyed the flavor in the shorter, 2 ml tank than when I put on the larger extension. I didn't fool around with it much, but I will be with my new one (still 24 mm) I really may vape the smaller size as I found the flavor much better. Will be interesting to hear reports on the 22 mm version, for sure.
If I had the funds, of course I would purchase the Kayfun Prime over the Berserker, but I think the Berserker is a fantastic little atty for the price, I actually enjoyed the tighter draw although yes, it is not very adjustable unless you get into drilling out holes and whatnot. Which I did not feel the need to do...
Anna