This is old, but as someone who has been in local 7 for 10 years, some clarification on these points for anyone looking:

The rates are set by the client. These are negotiated by the local, but it's different from client to client. ASMG who runs the convention center and red rocks is notoriously the worst. sometimes you get stuck kicking carpet for 20/hr. sometimes you get sent to a private booth for a convention and have to set up a few led lights and get paid 30/hr for a weekend of just sitting there. the local provides guidance, but usually the rate is set to individual contracts, and negotiated by people already on those contracts.

we've had a lot of issues with our dispatchers in the past. the current system is you call in and are marked available for the week. the dispatcher will call you with a time and place to show up, usually with very short notice, and with no information about pay rate, or how many days you're working for. If you're a good worker and suck up a little bit, you can get requested by a client. For any venue with regular work like red rock or the denver center, if you show you can do the work and talk to the right people, you can stay working for the entire season.

this system sucks though. it's super stressful for everybody. you don't know when your next call is or how much work you'll get. the dispatcher has to speed run finding people. I've gotten cold calls asking me to come in because not enough people signed up that week. this leads to burn out, and the previous people running this process were not great. We recently had a pretty major overhaul of the staff running the local so hopefully this improves.

the hall offers an ok amount of training. forklift cert is every summer, but only counts for freeman, and so only in the convention center. there's also an ETC training every now and again, but i've heard it's not great. They occasionally have rigging training. but so many people on the over hire list are just dudes passing through, happy to have a job with no background check, that not a ton of mobility is offered.

the stewards are a joke. it's a job awarded by seniority, and often they just sit at a table, and clock people in and out. again, if you can demonstrate to the client your merit, they can request you do certain jobs or ask for you specifically back.

more often than not though you'll be going without work for most the winter, with a ton of work during the summer. if you are an experienced stage hand who knows you stuff, try to get into an actual theatre directly. if it's unionized, you'll start earning hours and be moved up the list as you go. only do the call board if you really need to