Just confirmed with OGB; unfortunately, he can't do a 14.5mm straight stem.
As such, I'm gonna go for the standard 14.5mm GONG adapter with 12mm (Diameter) by 10mm (Length) stem. Diameter is not quite the same as the inner stem on the PonG, but is close enough not to touch the bullet and the length is the same, so it will not require resizing the PonG, just fitting the mouthpiece through the plastic!
This will also sit perfectly on top of the white inner ring in the PNP chamber (which I suspect was engineered to minimise transfer of heat to the PonG ironically enough!). The glass GonG will still not touch the bullet at all.
Bad news is that it is gonna take 2 weeks to deliver to Australia. Ah well, I'm waiting on 2 other shipments of parts for it too! @
emmdeemo do you know if the pinnacle microshower water tool fits on the end of the OGB adapter, or do you just use the mouthpiece you made on it's own?