[Ashlandchris]

I recently did similar and tried to respond in the order of the pms. I sent an e-mail to the 1st "pm"er and asked if they could confirm request and gave paypal details. I then replied to other "pm"ers and advised that they were on my radar and I was awaiting confirmation.
In 2 instances the initial pm sender never came back to me so I moved down list.
All were very polite even if they missed out.

I am not sure of official etiquette, but your suggestion sounds ok. I may be tempted to not say they are sold until the shiny coins are in your mitts, but say "sold pending payment - I'll come back to you if it falls through"