Having read all this and tried all the methods, I agree with everything. But I have some experience/thoughts.
I gave up on smoker boxes -- just too much trouble. The last three I had (they do deteriorate with the heat) I removed the lid hinge pin and just laid the top or the bottom across my flavorizor bars. Much easier to add chunks for longer cooks.
Foil with holes works too, but I feared melt so close to high heat.
I stopped using chips in favor of small chunks -- 1"-2". As a woodworker who lives in the woods, I always have tools and wood in some form to make my own. Kiln dried lumber may be too dry. Air dried is best (about a year minimum). Don't use fresh cut wood. (When we made a trip through TX, I stopped and bought a cheap bundle of mesquite firewood. Got lots of smoke wood from that.
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Smoker tubes with pellets work well. I put a 50% - 80% full tube, depending on how long I want smoke, on the side burner to start as shown in the first page, then placed on the main grate while cooking on my custom upper grate.
All these can produce smoke flavor on the meat surface. I have never successfully gotten a true smoke with smoke ring on a gas grill. For that, a smoker is needed. It's about more than just smoke.
As for above or below grates, above may work with light "meat" like fish, fowl or pork, but for beef I always go for smoke below the grates -- so I just do below for all.
And for "smoked meat", I use my WSM. I've employed many techniques on my Genesis to get a real smoke ring in a low and slow cooked pork butt, ribs or a brisket, but never got the real thing. The right answer was with the new-to-me 14.5" WSM. AH-H-H! smoked meat!