Interesting way to vape flower. Seems like you’d want something smooth like a shower head percolator and you’d want the joint to be on top of the percolation chamber. I recommend adding a “drop down” glass adapter so that any oil produced by the condensed vapor drips down into it and can be easily cleaned out, and so that you can keep heat off the main glass joint, because things like the flowerpot or a concentrate e nail can snap glass joints if there’s too much thermal shock/it gets seized onto the joint by heat shrinkage. It’s happened to me too many times unfortunately. Always get something cheap you’re not willing to lose to put your enail or flowerpot on, IMO. Otherwise I would say a coarse fluffy flower grind would probably work best with this. cheers and happy vaping