I see. I don't think your will get a clear advice with what weighting to go ; its really up to you. You also must have an upfront rules how to handle future additions/delisting ( and this is not so easy as its sounds). Here are some scenarios : 1. Buyouts and mergers 2. Add new 3. Delete existing 4. Dividends ( for total return) BTW , never heard of volume weighting.
I was thinking that it would give more weighting to stocks that are in play more than usual. Just a thought.