A lightweight .460 w/ no brake doesn't sound very fun! My .460 had a built in Pendleton brake that blended perfectly w/ the barrel and was difficult to see. Even though it was a stern taskmaster for poor shooting form, I never minded shooting it off an upright bench even w approx. 85ft/lbs of recoil energy. Shooting 16lb bowling balls at a 100 yards with a 500 grain solid was pure joy!
Regarding your .378, sounds awesome! Even the name, ".378 Weatherby", invokes awe.......and makes weak men wet their pants!