For GAF, all three of these revolvers can be used in EoE, and both the Colt NS and Webley are main match eligible as well, paired with an apropriate rifle. The .45 acp/AR are considered acceptable substitute rounds. Half moon clips are allowed in EoE, with .45 ARs needed to compete in the Victorian era main match classes.
excellent video. Pair the Webley with an SMLE for EoE, or an MLE/MLM or even a Martini-Henri for the Main Match. The NS Would work with most anything from the 1890s, as it was private purchased by officers around the world. The N Frame Smith dates from 1908, thus could not be used in the main match, but a fine EoE sidearm.