I can see where there would be a change if you made it mid-cook. I usually set mine up when new and don't mess with it, just learn how it cooks and go from there. That being said, I have the "Weber" adapter on one of my kettles, and I like that has the deflector since I mount it below the grate in one of the intakes.
If I am making the hole, I try to stay just above the grate. No chance of anything dropping into the adapter and into the fan.
I have used my guru mostly for drum cooking. Completely unnecessary but it was a gift.