Do they really work that well? Not sure who I would block the bottom holes though....
I had assumed air flow was my biggest problem. Which I why I drilled out the bottom vents and added a couple of new holes. With the though that I could control temp with the top vent.
The only way I have had good temps (150°c and above) is to dump in 1-1.5 chimney of roaring briquettes in. Pile the either side (a bit like using baskets). The temp runs away and I can’t really control it. Shutting the top vent in the beginning and opening it as the temp starts to drop helps some what but it’s not great. I have found this the best way to cook a Kelly bab, without a rotisserie, just lay the meat on the grate
I tried a bag of heat beads last year with similar results. Thinking the Big K coals were the problem.