I have shot a PM to devouringone3 to ask for pictures of the goop in Joe Grado's modified version of the HP. Hopefully he is still checking PMs/getting emails for them and still has the headphones or pictures of their interior. I am interested intrying this, both with some bog-standard SR60 drivers and the Sennheisers.
Indeed they are. I have a Grado cup modeled on the a Beyerdynamic cup's dimensions that, through much a use, uses a G-Cush pad. It sounds just a little too anaemic with all of the Grado drivers I have tried. The mass flattens them all out. The PX95 might fit the bill for them perfectly.
...built these today. I beleive I have the PX95 drivers in them. I can confirm @wje 's findings...these are bassier than the PX100 ii. I plan to move them over to something that might just suit them perfectly after a day or so of trying them in these...
It's the cheaper version of the Auvio headband that wje discovered at Walmart, and the cups are a pair of Cabillas' that I have had lying in reserve for a while now.