What projectile within the sabot? Normal lead slug? Or something else -- a copper pettled variant? I have long wanted a Marlin in 45-70, but all I have at this point is their 16.5" carbine in 44mag.
If I had to go into bear country, I'd want something quickly deployable. There is no discussion here of carry rigs (the author assumes a handgun, and thus a holster). But if one were carrying a shotgun or level-action rifle, then one of the tactical slings with forward carry makes sense. It needs to be an "always on you" solution, if the intent to provide ever ready bear defense.
Sabot slugs penetrate better than foster slugs. Smaller diameter. I don’t think the coating makes much of a difference. I bought my son a Marlin guide gun in .45-70. I have it loaded hot for Marlin in lighter weight slugs (300 grain). This is deer medicine only. I also load them up to 500 grain bullets. The hotter loads would blow up my 1884 trapdoor Springfield. So I have strict labeling to prevent me from using them in the wrong gun
If you don’t hand load 450 Marlin might suit you better. It is basically internally identical to 45-70 only the rounds won’t chamber in a 45-70 gun for safety sake and is much more powerful than stock factory 45-70 round