Both the issues you describe are related to leaky orings. Sprung powercores are a bit more forgiving in terms of avoiding FSDO, but they don't cure the issue or help efficiency. Orings wear out, so ultimately you need to learn how to replace orings to have a properly functioning marker in the long term.
My suggest would be to set your board to stock settings and then bump the dwell up to 16 ms. After that, I'd recommend completely rebuilding the powercore including the outer orings as well. The issues you describe means that at least 2 orings aren't properly sealing.
In particular, make sure that the size 17 orings as well as the bolt sail (size 16) are all a little bit snug. I've had terrible luck with buna orings. Use urethane or hnbr (green orings).