Jimmy, there are 2 kinds of Production managers - those who will return your calls/emails quickly and those who won't answer anything but the dinner bell.
I ask for a *current* stage plot and rider. If you've already gotten a rider through the promoter or venue, make sure it's current (because it probably isn't).
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We set up and pre-wired the stage according to the rider and when the band came it, one of the horn plays went back to the bus. When we asked what was wrong the keyboardist said, "you set up 4 horn mics." "Yes, that's what was on the plot". "You must have got a really old rider, that mic is for a player who died 3 years ago, and the guy that left? That was his best friend." Groove busted...
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The other thing - the rider will likely have a number of "requirements" that you cannot meet, or at least cannot provide with the amount of money in the promoter's budget. Some of these things may not be critical, others will be must-haves. Discuss this with the PM in advance. Nobody likes surprises upon arrival.. If something is absolutely critical to their performance you'll need to get approval from promoter to increase your fee to cover the additional equipment rental (and delivery and other expenses). If the promoter is reluctant, call the PM back and say "I'm sorry, the promoter isn't approving the additional expense, you'll need to talk to him/her about that. In order to have your special mixer/mics/tube DIs/widgets sent in time for your show, I need approval by xxxxx." NEVER hire in extra stuff until you have WRITTEN approval for the specific gear and monetary amount from the promoter, or you will eventually be stuck with the bill. Trust me.
Some PMs will defy advancing (which is what you're doing when you call the PM). My final voice mail or email to those types of folks says something like this: "Hi, this Tim and I'm calling you for the last time regarding the performance of (band name) at the (venue name) on (date). I've reviewed your rider and have left several VMs and emails, none of which you have responded to. If you don't care enough to advance this show, please don't be a whiner when you show up and things aren't the way you wanted."
I c.c. the promoter in all my advancing emails so he/she is aware of the quality of communications between the act and my employer. When the PM becomes a jerk because he didn't advance the show I can point to the promoter and say "you have all the emails, tell me why me and my crew should be his whipping boys?"
All of this, Jimmy, to tell you that in spite of your best efforts, chances pretty good that 50% of your acts will never advance (or sufficiently advance) the show.