A little late, but thought I could provide some input..
I currently work at a very large casino that has a constant stream of new games, so I get to see a wide variety of progressive attributes. Although 1% may be typical for an older $1 game, it is not a standard or even a max. I have seen $1 games with as high as 2% increment. For base settings on older games (S6K, S2K, etc..) it is typical to start the progressive (reset amount) at the top base game win, so if your max win is $2000, it is common to see the progressive start there. I'd say anywhere between .25% and 1% is reasonable in this case.
For calculating accrual I find it reassuring to use a custom calculator.. Excel has all the functions to make a very reliable calculator based on coin-in, or whatever mech your progressive uses as its funding source.