I used to do some plinking with a 458 and some jack rabbit hunting with lead loads. For me the Lott is too much of a good thing, if I was a PH then yes I would get one. With age my recoil threshold has gotten lower (or maybe I got smarter, not likely). Now the 375 H4H is about the tops I am willing to put up with. Even when younger I would dread bench resting full house 500-510 grain loads unless I had a standing bench rest set up.
Back to the original question as local a gunsmith as possible is my first choice. With that CZ though I would completely trust African Hunting Rifles to do their wonderful conversion especially the stock work.
Cast bullets can be tricky, with light loads a filler or an over shot wad has made a big difference in eliminating flyers. For the 458 I always used lead loads for the 45/70 as so much development has gone on with the 45/70 with lead loads. These were great fun rounds to shoot.
