Seems that Shakari already answered you in regards to what considers fast enough handling.

I'll lean back and get comfy in my armchair and toss in my $.02, tho...

IMO it is your purposes here, Alan, that describe the "African niche" for the Marlin 1895 in .45-70. I'll go so far as to state that it would rank as high as just about anything else when loaded with 400 grain bullets of a variety of type from my long-shaft cast hollow points to jacketed soft points and running at 1500 to 1800 fps. My 402 HP goes 1640 fps and is a killer on game and in test media at short range duplicates the .375 H&H Magnum when that caliber is loaded with Premium jacketed bullets.

My Marlin is from the first year of Ballard rifling and has the 22 inch barrel. Even on a huge leopard, the gun would absolutely kill from any angle and break bones the whole way. Weight is around 7.5 lbs and handling is really superb. For shots from the front sight to 100 long paces, I really can't imagine anything better for handling of the rifle when mixed with killing of the leopard.