Shockers can be run on both HP or LP tanks. If you would prefer to use a LP tank, Crossfires are recommended due to their fast recharge rate. Some people have said to stay away from HP tanks, but I (as well an MANY others on this board) have seen otherwise - THEY ARE FINE TO USE.
One thing to make sure is that before your air your marker up for the first time, back the HPR down so you dont overpressurize the system and blow the gauge and/or solenoid. Also, for the times after that, slowly turn the tank on so that the air doesnt "shock" the reg.
If you have an adjustable tank set the output to 650 psi