The "other" features are just allen wrenches for the sights.
& the sideplate screw & the grip screw & so on.
Gauge should be 0.006".
EWK usually has multi-caliber wrenches in stock that are way better made than the DW/CZ ones. They also have lots of other kewl DW stuff too.
One big advantage of the DW switch barrel & shrouded barrel system is that scope mounting is easy as you only attach to the external sleeve, no drilling of the actual barrel. Personally I like a 6" vented heavy rib barrel, but that's on a .357, if I went with a .44 I'd probably go to an 8".
Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”?
Elderly Hunter: “That's dashed unsporting. Probably Belgium.”