Knowing the number of bidders on a piece is not as clear of an indicater as you may want it to be. Pieces listed with a low opening bid will most often attract the greatest number of bidders but the final sales price will still fall in line with the high opening price with only 1 bid. Also affecting the number of bidders is the amount of time the auction is "on". 3 days will have less chance for multiple bids than an auction of 7 or 10 days. Another consideration for the number of bids could also be affected by the day and time the auction ends. How much bidding will be going on Sunday during the Super Bowl? So, unless you really want to get into all these variables, I would suggest not paying a lot of attention to the number of bids.
Another point I'd like to make is that if you ignore the reserve auctions that don't met the reserve, you will be missing out on counting bidders' "maximum" bids. Just because a seller sets his price too high, doesn't mean that the piece doesn't still have a value in the market. ( Its value is what a bidder is willing to pay! not what a seller wants for it! )
Aword of explaination; I have been tracking a good number of HL's on Ebay since Sept, in order to gain the same info that you are now seeking. I only follow Limited Edtions (that's all I collect) and I do include all pieces ( ie: variations, edtion #, Dutch Auctions, no box, damaged pieces, etc.) These gives me a good feel for what is really going on with Ebay. It is sort of like they do with the Blue Book for cars or a guide to coin collecting, they give you the range of prices depending on condition, mileage, etc.
And yes, HLs that are signed or have a low edtion #, do sell for more!
Jeff