You won't experience problems with a never seizing lubricant and black powder.
In fact most of the problems attributed to black powder fouling and petroleum based lubricants don't exist any more than problems of fouling build up with natural lubricants. Pay attention to the condition of the barrel when shooting. When you feel a crust ring building up at the breech or the ball is getting hard to load, wipe the bore with a loose fitting damp patch to pull out the fouling and clear the crust ring at the breech.
Some of the best rust inhibiting products, Barricade, Boeshield, are petroleum based.
Using the all natural products such as bear grease, lamb tallow et al is a romantic notion that follows historic practices. Doesn't hurt and does protect the bore, but not much better than some modern products.