With a scheduler I don't know well yet, I usually respond to an email advertising the shop indicating that I would be willing to do the shop for $X 'because . . .'. This is where I put in the reason why this location should be paying more than it is to be acceptable to me--distance, time on site from experience, orphan shop, etc. I don't beat it to death before thanking them for their consideration. Sometimes they bite, often they don't.