Fuji compares there only conventional guide sets. I'd say we don't know exactly the differences, for that we would need to measure the actual line friction. The casting sport guide sets have usually a larger diameter and height (I don't think a 50mm guide makes much sense for practical fishing though).For sure that is the bottom line and indicates that line slap may not be as detrimental to impacting casting distance as I would have thought.
Lefty Kreh recommend a larger stripping guide to reduce line slapping. I could imagine that a small action cam mounted to the fly rod would work to record high speed footage of different stripping guide sizes. Maybe someone here has the time to conduct such an experiment.
George, thanks sounds quite interesting I'm guessing that's for an trout accuracy rod. I've used Torzites, but not yet such a small size.
Torsten.