I've always just bought the tiny expensive bottles of genuine bicycle chain lube. The other day I mixed up a few ounces of home brew because (1) I didn't have any chain lube on hand and had the ingredients (odorless mineral spririts and motor oil) on hand. and (2) I thought I'd try it since it seems to be commonly used. I think I did a 2:1 or 3:1 mixture OMS: oil - I think it was straight weight 30 that I have on hand for my lawn mowers.
(by the way, it works great - seems to be as effective and clean as "genuine")
Made me wonder - what do the mechanics on the pro tour use? I'm not talking about bike shop mechanics, but the pro mechanics that are on the road supporting the racers on tour.
I really can't see them using the tiny 3 ounce bottles we all use, but maybe they do, maybe just supplied by the case by sponsors and just use the little bottles and go through several bottles every day and just toss the empties?
Or do they have an oil drip type dispenser from which they either dispense bulk "genuine bike chain lube" or do they use home brew?