Originally Posted by
oldbobcat
The limit screw is only there to keep you from flipping the chain off while you're shifting. The derailleur height only affects the accuracy of the shift while you're shifting. When it's too high the flexibility of the chain comes into play. We want to minimize that effect. Optimum is 1-2mm. There are malignant cases where you'd want to go higher, but there's no need to go into that here.
Looks like I responded while you were adding this. You're saying that both adjustments are only a factor while shifting, but I was wondering if the bottom bracket shell flexing (i.e. during a sprint or climbing out of the saddle) could play a part. Perhaps not.