Orange is on the right track. As a check, the rule is two and a half to three times a salary. Thus if a Chief in the area was turning $60 65 Large per year, s/he's doing around $30 an hour (using a 2,080 hour work year). So, $75 to $90 would be in line. If we're talking heavy experience and night work, scale it up appropriately. The neophyte pulling and punching wires for a studio would scale down appropriately.
Set your price, and be prepared to walk away. Those who want cheap are used to buying cheap and complaining about the results. Let them buy elsewhere. When I did much more pickup work, I figured what the time as worth to me and quoted. For those few who were concerned, "I'm sure you'll be able to find someone. Good day."