As little as possible!
Seriously though, there are regional and local "norms" that will give you an idea of what people with your experience might earn in that area.
The biggest factors are your qualifications, but the determining factor is what the market will bear.
For example I would love to be able to pay $40/hr to my climbers but there isn't a customer in my area who would be willing to hire my company for the hourly rate I'd have to charge in order to pay that amount.
Lots of people ascribe to the opinion that the "owners" are greedy and won't pay thier people a living wage.
I find that generally laughable.
While there are some owners that are that tight, by and large it is the customer who keeps wages low. Most are simply not willing to buy a product that is priced high enough to provide what they consider a "liveable" wage.
Its the same thing with the lie about "minimum" wages.
Everyone thinks its a good idea but nobody stops to think what that does to prices. Simple mathematics means that either the price of the product goes up to cover the added cost or someone doesn't get hired.
And if that min-wage position doesn't get filled, then productivity goes down, while demand stays the same...prices go up.
Anyhow, back to greedy owners, I also don't know of many (if any) employees that will come into work for weeks on end and not draw a paycheck when things are tight.
I guarantee that just about every business owner out there has done just that and will do so again when necessary. They will also do everything they can to keep work coming in so that they can keep their crews busy and to pay them!
So, rather than asking what someone is willing to pay you, why not "sell" yourself to your future employers by telling them what you bring to the table, what you will bring to the company, and then demonstrate that the wage you are asking for has a good to high return on investment.
Think about it this way, a $500k crane is a lot of money But if the crane can generate a whole lot more than $500k over the life of the crane then it is money well spent.
Paying you $40 per hour as a climber can also be money well spent if you can generate a revenue in enough excess of your wage.
Anyhow, just my $0.02 worth.