70" is absolutely a round ball twist, in any calibre.
Maxiballs were unstable upon impact with moose, when shot from 48" rates of twist, which is also a RB twist. It is not and never was a combination twist.
Those maxi's would not travel in a straight line, though the moose, turning on ribs and just muscle as well, tumbling inside and changing direction. A straight sideways shot
sometimes would not even catch a lung.
48" in .50 cal. was the standard twist for Hawken rifles made in the 19th century by Sam and Jake.
In .58 or .577 calibre, it was the ROT of the English Enfields & shot Minnie:balls well enough for the purpose as designed, for war.
The Beeswax and bear grease or oil would work fine, I imagine. Vaseline is a Petroleum WAX, not a Petroleum oil or grease of which neither will mix with or soften black powder fouling.
The Petroleum WAX will and does, just fine & is the ingredient which is used merely to "stiffen" the actual lube, the Petroleum wax.
I have tried using paraffin wax as well as Olive Oil in bullet lubes and had less than stellar results with those changes.
A tightly patched ball will shoot very well in that barrel.