dwell is the amount of time your solenoid stays open for. it's measured in milliseconds.
The lower your pressure is the longer your solenoid will need to stay open for to shoot the ball at 280fps(or w/e fps you are trying to obtain) This also means you won't be able to fire as fast as you would if you had higher pressure and a lower time the noid is open for.
You can always fiddle around with different pressures' and dwell settings to get to a spot where you want it. If you ever feel like you have fubar'd the boards settings too much just reset them to stock and try again.
I play mine at 185ish and I use the default board setting for dwell which is I think 28 or 38 don't remember right but it has the 8 at the end. I can go through 5 pods and a hopper on 56/45 tank and still have some...
first electronic gun- smart parts ion
first after market barrel- J&J ceramic 14" cocker threads
first barrel kit- Full Freak barrel 12"
PMR '09 red Ul'ed with ballin $0.99 silver flame drop haha
two rotors one in which I have never freaking used!