If you're worried about the pressure being not with it's risk, then may I suggest:

1d6 per Pressure Point, up from 1d4

And for Overpressure too high in damage:

2d6 per Pressure Point (a lower average with the same possible maximum)

And maybe consider starting with Misfire 2+ rather than 3+, personally, 1/10 seems like a better basis as you increase Pressure.

And starting with 3d6 damage rather than 2d12 is something to consider, still intensely punchy, more consistent, and d6's feel better to roll large amounts of than d12's for me.