At the Hefley rondy, the humidity was under 10% for the first week, until the rains started. After the rains started, with a humidity in the 50's to 70's, the air felf clammy incomparrison to the previous days, yet the barrel and pan fouling stayed quite white.
Taylor and I had NO fouling problems at any time with our round ball guns and cleanup was as always - easy as there was never any fouling buildup. This, we attribute to the ball/patch combos we use which demand the use of a short starter. He used a whindshield washer+murphy's for pre-lubed patches in his .50 and .40, while I used windshiled washer+soap for my pre-lubed patches in the .32, .40 and .69. At no time, was wiping the bore even remotely on our minds - normal easy loading throughout the matches, even when I was shooting in the ctg. match with heavy charges in the .69 - no fouling buildup, even from the 140gr. to 165gr. loads.
Incidently, I've heard of guys with little rifles, ie: .32's having trouble with fouling. I used the same lube, WWasher fluid with a bit of soap added, a .017" denim patch(8oz) (.020" with calipers) and a .311" ball. I haven't benched this load, but it seemed to shoot well. Too, it was exceptionally easy loading (I softened the edges of the crown prior to shooting it) with the stock 5/16" hickory rod - almost 2 finger loading once the ball and patch were several inches down the bore. There was never any fouling build-up in the bore. Guys having trouble with their small bores, as noted here before, might try this combination.
I've used an intermediate, over powder wad in the 14 bore when hunting back in the 80's and early 90's, but since Taylor's tests of last winter showed no powder degredation over a 5 day period using Hoppe's 9 Plus for lube, I'll not use a wad any more, mink oil or Hoppe's 9 Plus being the lube. The additonal step of loading a wad is not necessary for a round ball gun, it seems.
The best load for my .44/60 Sharps uses only a parchment disk on the powder, then the grooved lubricated Schmitzer 506gr. bullet with no wads and gives clean shooting in 70F weather, 30% humidity - no fouling buildup. Higher humidity should shoot the same, but lower might demand a lube disk or lubed wad. This load shoots into sub 1" for 5 shots at 100 metes off the bench - apperture sights, front and back.