Really? You'd think that since they aren't burning away the outer layers of plant material to release the cannabinoids inside of them. that more surface area to the ground bud would be better.
The herbalAire is the only one I've read does just as well if not better with a whole bud. Which I still find kidna weird.
I've found that the last thing I want is a perfectly consistent grind almost regardless of whether I want it more coarse or more fine. I want a consistent range of sizes from the granule of kief to pieces perhaps 2mm in diameter. I find that I get the most flavorful and pleasant hits this way.
Prior to becoming disabled, I was an educator at a children's science museum (Yes, it really was the best job ever). I think one of the models I built for kindergarteners to explore the concepts of volume and space packing of spheres might be applicable here.
Imagine a big see through plastic garbage can. The first thing I'd do is fill it with three basketballs. I'd ask the kids is this trashcan full of basketballs? Can I fit any more basketballs inside?
Then I'd pour in a big bucket of baseballs to fill in the empty spaces between the basketballs. Now is the bucket full?, I'd ask the kids.
I kept doing this with smaller and smaller balls until I finally filled it the can with a big bag of sand. This is the point where the children finally decide that I've actually filled in all the spaces between all the balls with sand.
So when the kids finally decided that the can was full of balls and sand, I surprised them by pouring almost half a trash can of water into the "full" can, and it was at this point that the kids understood that you could keep adding smaller and smaller balls into the can without ever actually filling all the space. With high school kids or adults, we could then start talking about the empty spaces between the water molecules or even the empty space inside of atoms, and it gets kinda mind boggling when you realize that the seemingly "full" can is actually almost completely empty space!!!! But with kindergarteners, we skipped that part of the lesson for more important things: playing with mud. I think the best moments of that job were when I would witness the adults in the room suddenly realize that the 4 year olds had a better understanding of a scientific concept than they did before walking into my theater.
So let's step out of the science demonstration theater and take a look at our grown up problem. In our situation, let's replace the water with the heated air we are passing through our cannabis. If we use the finest, most consistent grind, we can maximize the amount of material that fits into the given space, but we then limit how much empty space is available for the air and vapor to pass through through the material. With too finely ground material, I find that the heated air often opens up a single wide channel that scorches a small area but leaves much of the material untouched.
What seems to work best for me is to grind to a consistency where you recreate my trashcan of sports balls situation: a very few larger chunks to act as scaffolding to support the various other sized bits in place, but with a random distribution of sized particles to ensure that there are lots of different ways that air pass through the material so that it can be exposed to lots of different surfaces along the way.
And because this is the real world where each of us is a completely different individual using different devices to vaporize different materials, we have to use our big monkey brains and a little bit of science knowlegede to tinker and experiment with these variables each and every day with every new strain we meet.
For those of you who just don't care for science, you can just throw a little chunk in there and vape it. Once it is crispy, grind it into smaller pieces with whatever tool you choose, and then vape it some more.