My experience mirrors Jon's.
Here are some measurements I've taken. The "mod" 42s have between 0.005" and 0.007" constriction. The skeet guns range from 0.003" to 0.011" (yup). Full choke bbls have 0.016" to 0.020".
My repro came to me with Briley CTs. We don't shoot doves, but have an idea it would work just fine. Son and I use it for SC - mostly with the 0.014" IM. Repros are anything but whippy. Couple of repros took CH and RU at the ME state NSCA few years back. We sometimes use it in "Fluff" 12 ga events.
Field use in Maine translates as grouse/WC. I've used skeet/mod guns. In my hands, the full guns add nothing useful for those birds inside 25 yds. The 3" loadings are diverse; it pays to try different brands on the pattern board. For guns with less constriction try RP 3" #7.5s first.
