Mine (albeit with a firebolt as well) currently runs at 120psi, 9 clicks from bottom on the dwell, although can get it down to 4. It shoots 280 -/+4
To be honest you want set it as low as possible, without having to increase the input pressure. Drop your dwell and input pressure. not just one or the other. If you can keep a nice balance, then you will also maximise efficiency as well.
As a safe guideline if you don't want to fiddle too much, then go between 15-30.
Dan
NB: I'm assuming your recharge (ROF) is 0