Hang on a sec........
My understanding is that Unions do not pay union rates. Say the salary posted of a union job is $20.00/hr (salary would mean mngmt, right?) Your first 3 mths would be 60-75 % of the $20.00, say $15.00/hr Assuming you 'qualified" after the first 3 mths,meaning that you worked 40 hrs/wk and 3 mths straight at 40 hrs week, you would move up to the next pay scale. Of course, during the entire time your paycheck would be garnisheed union dues, yet you are NOT eligeable for any union benifits. Then again, my understanding of most unions here is that you can appeal directly to mangmt and aks them to waive the whole process and pay what you ask them to--whatever you negotiate with them. So much for Union representation, eh?
Now, my experiences have only been with the big chains in Vancouver, hopefully unions in other places are a little more.
Getting back to negoating: ,Take your current salary, add 10% and negoatiate with that. All kinds of confusing add-ons like benefits, longer/shorter work hours, need to be compared as well.