I was using the shorter 3rd party glass flower pedal bowl for some time now....but after going back to a "use the showerhead upside down" test yesterday on my 3rd party Elev8r bowl......WHAMO.....we have a perfect fit!
My 14mm to 18mm female adapter with screen in it has a slightly larger 18mm opening than the stock Elev8r bowl I tried to use first. The upside down showerhead would not fit inside the opening of the Elev8r stock bowl. But with this adapter I found at a local head shop, it fits almost too perfect. I can fit the raised top of the showerhead inside the top of the adapter and it is tight enough to pick up and stay on! But also it was not too tight and allowed me to remove the coil after the draw without pulling the bowl out of the joint.
With a perfect tight seal at the top of the bowl......it gets vapor quick....very quick. The screen/load is 30mm from the top of the bowl. This has taught me (after using that short bowl), that the seal of airflow through the head into the load works tons better if there is a good seal and no leaking from the showerhead to bottom of the bowl.
I'm now convinced that I could use the very short bowl without being too hot on the load or too close to the head heat source...because it was leaching so much of the downward air outside the top of the bowl and not directly down through it. This is because the bowl is about 3mm narrower than the coil nut ID.
With the very well sealed adapter bowl, I am doing temps down to 520 to 540 with nice vapor. Now I can experiment with temp to effects with a much tighter tolerance of heat from the bowl/coil. Before I could only sense taste and a small amount of effect differences going from say.....580 to 640. Now I should be able to have a much clearer sense of a 20F degree change in temps.
So if you have some of the 14mm male to 18mm adapters...see how they fit the top of the showerhead entrance....put a screen in there and use as a bowl. The 3/4 inch screens fit well with just a slight bend in them. Some of these adapters have a bubbled out area where a screen would go...you may need a 1 inch screen here with a bend in it.