As I see it, what you needed or were looking for is a needle control valve, and with that size of burner somethining like the 250 listed at TejasSmokers on their fittings/valves page.
What you ended up with, is controlling what appperas to be a low pressure burner with a adjustable pressure regulator. Now that is fine up to a point, but when you are running with higer output, like the pic with the high flame, you are not getting enough air for a clean burn. Yes you get more heat, and also more soot. Also you will burn alot more gas, a lot more ineffieciently, costing you more money per BTU gain. Now the cost might not be a big factor, but I wonder about the soot? One wants a blue clean burning flame,,,then the soot is eliminated. Otherwise one needs to open up the venturi for more air intake.
Just food for thought.