I haven't had my WSM all that long but I tried the standard method and it will run 300F and up with bottom vents closed and even with the top vent mostly closed but I was only cooking a small amount of food, not a feast.
Every session since then I've used the MM and the exact number of fully lit charcoals is 20 give or take your weather conditions and experience, IMO. Not half a chimney or some other vague reference. Twenty. I count them out by hand. 20 is not that much in my chimney (not a Weber chimney, but that doesn't matter).
Of course I lose count, so it might be 19 or 21 Kingsford briquets that actually gets in the chimney. The cooker temp is easy to control with MM and the vents, it's ready in under an hour to put the meat on and you could walk away for hours. You could. I like to futz.
Again, I'm smoking small amounts, 4 to 6 pounds and the MM method is the way to do that. It's completely logical that 20 lit will only ignite X number of neighbors before the 20 fall to ash and it's a lot easier to control if you don't start with grilling temperatures.
I don't taste off flavors from the charcoal, perhaps others do. I just feed me and anyone willing to visit. I may try using the count of 15 because it's about to get hot around here.