Note Taylor said the moose won't tell the difference - he is correct. The big cow he shot with the Bess, ended up with the ball underneath the hide on the 'off' side, expanded to about 1 1/8" in diameter. I still have that recovered ball, btw. A WW ball would most likely have ended up at the same location but non-expanded.
A friend has a .75 Sporting Rifle that Taylor built, and found when he reduced his charge to 120gr., he was able to keep a ball inside a moose. He-too used a .735" ball, but always WW metal. At 140 to 200gr., all he got were exits, which I prefer. He preferred to show the recovered balls at work, thus he reduced his charge. With a ball that size, about any powder charge will work, ie: kill moose, but there was a noticable difference on the animals hit, between a 120gr. charge and a 140gr. or more charge. It seemed, when the ball exits, there appears to be more 'nerve' shock to the animal, compared to one that stays inside.
In a large bored gun, one needs only a pure lead ball for most North American game. If I was going after Alaskan Brown bears with my 14 bore, I'd be loading 15 bore WW balls for increased penetration, rather than the 14 1/2 bore pure lead ball. For the unglulates, a pure lead ball would suffice, but a WW ball will give better results on heavy bones. The upper leg bone of a large moose will run 2 1/2" to 3" in diameter. For that, a WW ball is best. Even a 1st year bull calf has a 2" diameter bone in it's leg - tough on balls.
When shooting WW in a rifle, one generally has to reduce diamter .010" to .015" under actual bore diameter (calibre) and use a corresponding slightly heavier patch. When shooting WW in a smoothbore, .020" to .030" smaller than the bore is fine, allowing for a .018" to .025" patch.
If wanting to mix alloys, fine. Pure lead, as in 99% pure, will run about Brinel 5, while good Canadian WW metal is around 12 to 13(no glue-strip WW which are pure). Mixing alloys will allow easier loading than straight WW, but give a slightly harder ball than pure lead, thus inceased penetration.
In the big gun, I usually shoot pure lead (if I have it) for target, and WW for hunting. In the smoothbores, WW for target or hutning works just fine and is cheaper than pure lead, saving the pure for calibres that don't like it, like most all rifles under about .58 and most rifles with deeper than .012" rifling.
imho, of course.