Dude. Maybe I'm speaking to soon... But I froze my Griffin, used my leather belt to grip, opened up. Riwicked and coiled. And I'm flying in clouds, ty. Just hope no leaking tonight or so. 6hrs so far. Happy happy happyhad the same issue. If you can find a thin strip of leather to grip the knurly bit of the base you should be able to separate them.
Then change out the base oring to one of a smaller diameter, it will stretch out and become thinner making it much easier to remove the chimnet in the future and it will still seal well. The stock seal is a bit too big imo.