Hi Dennis
To give Mark Webber his due, there was the odd time were he probably could have won but was told not to pass his team mate.(sucks when you've got a bet on him). Hopefully this sort of thing doesn't happen in horse racing.
But you are on the right track I reckon. Jockeys are an important part of the mix, when trying to pick a winner. The problem I have always grappled with is how much weighting do you give to the jockey factor when compared to all the other myriad of factors that have to be assessed.
I spent a fair bit of time in years gone by following Don Scotts's handicapping methods and he was a big advocate of rating the relative skills of the jockey.
Jockeys too, go in and out of form just like cricket or tennis players.
Also you will find that some jockeys will be better in some situations than others. Some jockeys excel in their ability to read a slow muddling pace, others are better at rating front runners.
Reading back through my post I realise that I have only raised further questions without providing an answer, except to say that there probably isn't any one simple selection method based around jockeys, as baghwan's stats point out. They are steeringbthe horse, so they must have some input into the result. After all, they are the ones the punters abuse when a hot favourite gets rolled.