Does the one bundled with the purple heart model also have a similarly open airflow or not?
I agree that the included beaded stem is an improvement but as said the glass screen adds some restriction.
Not that much restriction but i am not a fan of glass screens anyway so i use the stock long glass stems (the long 'OG'-stemtubes without glass screen) combined with the glass balls and half of the cooling unit (hollow) as seen in this picture:
I use the one on the right the most (yes it needs cleaning
):
it has a rimless screen at the mouthpiece end (to keep the balls from clogging it) and a (hollow) half of the cooling unit at the bowl end (the screen is the bowl's end and the side with the holes the ball's end).
It has a very open draw (even in this reclaimriddled condition it still is pretty open but i have some reclaiming to do coming weekend
).
The other stem uses two halves of the cooling unit to keep the balls in and to shape the bowl.
Personally i am perfectly happy with these and they were "free" as they use mostly stock parts (i did change the glass mouthpiece because i like the mouthfeel of the Ditanium mp more and it has a wider inner diameter too...)
But again: very open draw. If i breathe thru the device with empty stem there's no restriction whatsoever
(well, there is now but it's really very dirty at the moment)...And the balls really cool very well without robbing flavor!
fwiw: I'd say go for the Purple Heart and add one or two long stock glass tubes and you can mock up something similar.
Pretty sure the cooling unit/short stem are still included?