As long as the cap is indexed properly on the notch in the housing, the rotor/cap relationship is designed to work. Yes, you're over-thinking it. You're not another engineer are you? We've got a bunch of them on the site that are so anal-retentive I'm sure they must own stock in Ex-Lax!
You could back up the distributor one notch on the gear so the spark has to jump forward a little at idle, but I don't think that's a good idea.
Jerry
