death by charts, page-77

Rule 1) Yes indeed - and there may be a level where a buy is a must - 2 for example. Also the speed at which the ratio changes could also be a useful indicator. Obviously a rapid increase in the gold price could change it very quickly.
One more thing there may be old buy orders which are well below the current price and one might need to discount those. Perhaps take the top five buys and sells or those within a given percentage of the last sale.

Rule 2) Worry about volume only inasmuch as you would be able to sell what you buy in a given period. If you buy 200,000 shares and the daily average volume is only 15,000, you might get stuck. It would take me about two or three weeks minimum to sell mine in normal times, not that I am about to sell.

You might end up Bungi2 of the Arc. At least you will be remembered!