You ask "What price would you propose if you were going to place an offer on this property? 15% below asking?"
I am getting the feeling that you don't have a "Buyer Agent" to discuss this with. That would be a good start, find an agent you trust and ask him or her that same question. I have been in the real estate business for 20+ years and every deal is different, every motivation is different (buyer and seller), and so I don't think you are asking what is the right price, but rather what is the lowest price I might think would be acceptable to the seller...
So, again, I am unaware of the sellers motivation. But I know the selling agent to be a good Realtor, meaning that the house is probably priced to sell. All that being said, properties are not selling quickly in this market. What helps them sell is a low price.
So you need to ask yourself, how high would you go for this one? Then determine the difference between the asking price and your top dollar. Subtract that amount from your top dollar, round it off and start there. So if you are willing to go to $750K, and can show financing ready to go, then do this: Take their asking $825, subtract your $750 (top dollar) and you get $75K. Then subtract $75K from your top dollar, getting $675. Offer $675 as is, quick close, no contingencies except financing which is already in place. When they counter, increase your offer, and add in your contingencies (home inspection, oil in tank conveys, maybe a house still to sell etc...) You may go back and forth a couple of times, each time splitting the difference, until you both arrive at $750K. You are not wasting the sellers time if you are genuinely anxious to buy the house. Just don't kick tires in this market, you will quickly become persona non grata.