

and the horizontal dropouts look like this...


On both of my current road bikes I have near-vertical dropouts and when fitting the rear wheel I always ensure that the axle is sitting in the dropouts as far as they will go (which is why I always have the bike on the ground before I tighten the skewer).
What is the deal with horizontal dropouts? On the inside of the dropouts there is clearly a shallow dished out section that looks like it is the intended spot for the wheel axle to be mounted, but if this is the case then it would mean NOT pushing the axle back as far back as it can go. If this is the case then I can see why it would be nice to have the adjustment screws fitted to the dropouts (although they weren't on the frame when I bought it).
Oh, and this will eventually be a geared bike (not fixed/single speed).
How do you determine the correct placement of the rear wheel axle in horizontal dropouts?