I suppose eBay is, by default if not otherwise, the best "market" indicator. But make sure you're comparing apples to apples. I see too many ads for cameras that say they work fine, but when you inquire they haven't been used in years. Or have inflated shipping. Or are sold "as-is". So if you go through the effort to test the camera, describe it accurately, and offer a return privilege, I would expect a modest premium over average eBay prices.
If you're looking at eBay selling prices, ignore the "buy it now" prices, since they may have had a unrealistically low "buy it now" price. Conversely, toss out the really high outliers, especially when the winning bidder had a very low feedback rating.
If using KEH, you can look at both selling and buying price from them and price yours near the midpoint. But keep in mind that they grade conservatively and deserve a premium for that and their reputation.
I don't think you should be concerned about being considered a chiseler by setting a high price unless it's ridiculously high. As long as you describe the equipment completely and accurately (as I'm sure you will) the buyer can make an informed decision.