Thanks! Happy to help.
I got the facts nailed down in the spreadsheet, which helped to easily discern who was realistic on their asking prices and who was ridiculous.
Ridiculous, though, can go 2 ways. 1) I have no idea what my plane is worth so I'll ask the highest market price and see what happens and 2) My wife wants me to list it because she hates me flying but I don't want to sell it. 2's get shaken out with the first attempt at contacting them (if you feel the need to). 1's will be excited to sell, but justifying a reasonable asking price may shatter their hopes. Along with reasonable data as to why you're asking what you are, they'll most likely be reasonable in accepting your offer. It's a justification thing... I'll justify why I'm offering you X, and you justify why you want Y. That's a typical negotiation, and usually the data wins. BTW, that was my plane's situation.
As far as selling prices go... that's a toughy. First off, Vref was completely outside of reality for me. It is dated (CRT radars, but no Aspen's or ADS-B). Totally worthless. I found the Mooney tool to be fantastic. The Mooney guys do a great job at keeping tabs on market trends.
http://www.themooneyflyer.com/tool.html
I used that to determine what selling vs. asking values should be with Mooney's, and then adapted it to the Pipers (ie. 10% below average asking, 15% below average asking, etc). That was how I based my initial offer.
In fact, when I made my offer on my plane, I sent over the spreadsheet with tail numbers, etc. to the seller. Basically said here is a listing of your competition, here is my offer, and here is why I am offering you that. It was a very fair proposition. I wasn't looking to screw the guy, and he knew that. We remain buddies to this day. He was also very emotionally attached to the plane, and you'll find that is common, as well. That's a tough one to break. Most people don't think rationally when there is emotion involved... so be as data-driven as possible. Emotion cannot argue with that.
Also, stay away from brokers. Buyer and seller side. In the aircraft case, at the low end, they monkey up deals more than help. Until you get north of roughly the $400-500k market, they just get in the way. Just make sure you have a friend who has owned an airplane that can help you out on the first one. Reading logbooks and discerning red flags is what is a huge deal.