Dave, pop in & have a chat to the boys at your local SSAA range & get a shoot calander. Yes as 500Nitro says there will be a shoot in Dalby this year Group1 to Group3, double rifle events, black powder etc - very late October, sorry I haven't got dates with me Unfortunately I can't make it this year due to family committments at that time. Have a chat to your gunsmith & see what he can do for you about info etc for these shoots. Well worth the phone call to an older Townsville gunsmith also.
If you can fire a .458 OK then you are fairly immune to recoil, but if you're like me & don't get much trigger time then you won't fire it as accurately as you would like....the old addage of pratice & then more practice!
Don't go too big too soon, the 450/400 No1 sounds a nice rig & you can load it down/cast etc.
You're on the right path mate, just take a little more time, try a few more rifles etc & then make an informed decision. As to buying a double mate well that's one hell of a lot of money i wish i had, only a pipe dream for me that one.........bloody envious of you if you can afford one!
93x64mm