Homesteader: Loading a revolver in the field, without the benefit of a loading bench is a royal PITA ! YOu have described the process pretty well. I tend to take the cylinder out of the gun, wipe down the nipples, and with the rest of the revolver holstered, run a patch down with a ramrod to clean out each chamber. Spit temds to remove most fouling. Then I put the cylinder in the top of my pants pocket while I use a patch with spit to clean the frame and the back end of the barrel. Then I use a spit patch to clean the barrel of crud.
The cylinder goes back in the gun, and how I load powder determines what happens next. If I am using my horn, and adjustable measure, I sit down on the ground, cross my legs, and cradle the gun in the crook of my knee, muzzle up, while I pour the powder from the horn into the measure. If I have a flask with a precut tube in place, I do as you have described. However, I was using reduced charges, and a filler of corn meal on top of the powder in my last revolver, so I use the flask for the corn meal, and my horn and adjustable powder measure for the charge. powder went into the chambers, all six, then I used the flask to put corn meal to the top of each chamber. Finally, I put a ball in one at a time, move the cylinder to put the ball under the rammer, and used the rammer to compress the corn meal and seat the ball just below the surface of the chamber. When all six chambers were loaded, I would use grease to put around the edges of each ball, to seal the individual chambers, and provide some lubrication to keep fouling soft as all six rounds are fired through the barrel without cleaning. A new lube that reduced group sizes for an experienced revolver shooter is: 1/4 WD40 oil; 1/4 Mobil One Jet Engine Oil, 1/2 melted beeswax. mix the three ingredients together when the wax is liquid, and let it cool. You will get a soft lube you can use to circle the balls in each chamber, that will resist melting or burning from the flames of the adjoining chambers, lube the barrel when that chamber is fired, and provide better accuracy.