Well that makes it EASY!
Three long magnum actions in Winchester model 70.
Three barrels from Douglas, one in each of the three calibers
Three each trigger assemblies, safeties, mounts and scopes
Three stocks - reworked to fit the barrel profiles
A smith to do the truing of actions and bolt lugs, barrel fitting and chambering and then the time to assemble the rifles and put together some starter development rounds.
All thats left then is to finish working up good loads for them and a nice trip to use them on.