Rich-

That's (for me) the most important aspect of 'load development' for my hunting rifles -- right next to basic regulation for the Double Rifles.

I've had success with quite a few different recipes for patch lube, including Thompson Center Bore Butter (which some guys have some particular problem with, not me), Bear Oil (that I rendered myself), Lehigh Valley Patch Lube, and a few recipes I've gotten from here and there - including a couple from Daryl.

With a thick, tight patch you'll have a fair bit of latitude on *how much* of whatever you use, the thickness of the material can carry plenty to get your bore moist from breech to muzzle, and the tightness gives you the chance to get a really good gas seal for the duration of the barrel time - keeping your load from blowing the patch lube past the ball along with the pressure of your burning powder charge.
Gets you consistent velocities too.

The *how much* is part of the trick, and is pretty easy to sort out as long as you have a lube that will work in the first place - you need to consider the range of temperature you'll be dealing with on your hunts. Will the lube freeze in the bore? Will it turn to drool and spoil your powder charge or run down the bore in hot weather?

Once you have settled on a lube that's suitable for the elements you'll simply need to get to the 'just enough' to keep your bore consistently moist from breech to muzzle after the shot and no more. With Bear Oil or Bore Butter or Castor Oil/Murphy's Oil Soap mixture, I'm good for as many shots as I'll shoot in a day, and have a good fouling in the bore for the next morning - again, with no corrosion problems.

Note that I don't run corrosive percussion caps, and I do take good care to completely clean the rifle when it gets back home, oil it properly, and store it properly.
With the right load components, care for the blackpowder rifle is simple.
The only solvent I use for cleaning is cold water.

Cheers
Tinker