I will be trying this out with the J-Head... I'll report back on how it goes.
However; I am beginning to be fed up with the J-Head since I've been having issues with the PTFE liner... I will be looking to get a full steel hot end in the near future! (wink, wink...)
I can't help but notice this derivative by Komb; its for the Wallace though, but I think it's worth a look.