Hi Herb - glad to see the extent of your testing about mirrors the way I do things as well.
In my 42" barrel, 75gr. 2F, 65gr. of 3F or 55gr. 2F all foul about the same (I can't see or feel any difference) - never a problem with loading and I don't wipe - never have, except when testing accuracy of wiping against shooting dirty.
I've been using the 55gr. 2F charge only because I had 4 pounds of 2F and very little 3F - enough for my wife to use in his .45 for our Rondy is all. The best groups I've made with this charge are still double the size I get with 65gr. 3F and a .400" ball and .020" denim patch, LHValley lube. The light 2F load will hold at or just under an inch at 50 yards. Incidently, this 1/2" grouping of the .400" ball is identical in size to the load I found works best in my GM .45 barrel for the same gun - 42", 60" twist, 70gr. 3F or 80gr. 2F, .445 ball and .022"(blue -10oz- denim) patch, LHV lube.
I tried 75gr. 2F as well as 65gr. of 3F with spit lubed patchs, and found the accuracy wasn't quite as good with those loads as with LHValley lube. I am elated with the accuracy and velocity of 65gr. 3F and the heavier 2F load, but they are hard on my meager supply of powder or both grades - I'm about out. I"m hoping hatchet Jack can sell me some to do until Hefley Creek where I can get some more.
I've found the lighter 55gr. load with a .395" ball will allow a thinner patch than the .020" denim (8 ounce) that I use, but I am leary of using a thinner patch that might not stand up in the increased temperatures which are bound to happen at Hefley. Thus, I use the .020" or even some .023"(black- 10oz) that I have as well. I've also found the .400" ball shoots identically to the .395" when using the light 55gr. charge of 2F, however 65gr. 3F and 75gr. 2F shoot better with the .400" ball and a .018" to .019" "cottom duck" . For Hefley, I'll just sight for and use .020" denim and 65gr. 3F for the entire shoot as it loads easily, shoots cleanly and is the most accurate load I've found so far.
Herb - my wife's .45 GM barrel, only 32" long, shoots very well, about 3/4" at 50 yards using a light charge of 50gr. 3F, .020" denim, LHV lube and a .440" ball. I've done only a little load developement with this rifle, but know it'll shoot better with more load development. She shot about 25 rounds last Sunday, her first ML shooting since our first daughter's birth, 28 years ago and had no difficulty loading - no wiping needed, of course.