Well, if 51 years of shooting percussion revolvers makes me experienced, I'll give my 2 cents. Muz load rifle yes, I load using a horn and measure. Six shot cap and ball revolvers, load using a flask with screwed in spout with spring loaded lever that shuts powder flow via a flat metal plate. I have various sizes of brass flasks and various marked screw in spouts, each of various lengths that allow a premeasured grain weight of black powder to be dumped into each chamber of the cylinder depending on what revolver I'm shooting, anywhere from 18-50 grains.
I've used a powder flask to load cappers all 51 years of shooting them. In the early days I did check from time to time to see if any still burning remains of black powder were still inside a chamber, never saw any, have read a number of times basically what 'akroguy' posted. I did try the method of pouring black powder from a flask into a powder measure then dumping that powder into each chamber of the 6 shooter several times, but that method is slow. Even slow if shooting and having a table or whatever by you, but many times (most of the time) my shooting is walking and plinking along a river or through wooded area and doing the flask to measure routine would be a pain and slow.
Reference what 'ppg1949' posted about the metal plate attached to the spring loaded lever not closing all of the way and allowing more powder than wanted into the chambers, I had that happen once to a flask. Noticed it right away. If you are paying attention to the loading process and have shot any percussion revolver enough times, you can see what level your needed powder volume is in the chambers and if powder is still flowing from the spout after releasing the flask lever when you pull it away from a chamber, well---tells ya something is wrong. I had to repair the lever to plate attachment and all was good to go. Guess bottom line is to use whatever method you want and feel secure. I'm very safety conscious and wouldn't be doing loading from the flask if I felt there is a danger of having an 'explosion'.