How's that for polar opposite experiences Tom! :^)
My bench testing has shown me if a bullet is swaged down due to tight cylinder throats, accuracy suffers. I found this true for my Redhawk and Bisley in 45 colt. Using identical loads (components, bullets) with the exception of bullet diameters, I've found that a tight, push-through bullet fit gives me accuracy in the 1" 5-shot range at 25 yards. Second best groups came through using slightly undersized (easy push-through or slip through fit) slugs for the cylinder but not the bore. Over sized slugs (for the cylinder) gave me groups in the 2-4" range at 25 yards. The best way to determine what you will need is to shoot both and see which diameter shoots best from your sixgun.