I appreciate the advice on how to do it. However, I don't do much handiwork other than change light bulbs. I was just going to send it to Mike Myers at Walker pipe. Seems safer, especially for the Dunhill.
As always, Mikes advice is sound.
I've thinned a few of my buttons as well. I should probably measure them and find out what mm thickness is my sweet spot.
Rarely is it the shank air passage that is restricted. It is usually the stem.