Can you run it without any disc to give the most AF?
Hope you're doing well mate....
Thanks Charlie. Doing ok.
Yeah that was my first inclination. AF open all the way but found it had a bit of a whistle - very noisy.
I thought it might have been my coil placement but then
@ShowMeTwice mentioned a post by Rob Fisher on ECIGSSA where Rob had the same problem and used a Dremel tool to bore out his 1mm air disc into a 3mm hole. This fixed the problem for him.
I don't have the tools (or a boat house to store them in

) so I mucked around today with some Torx drivers in lieu of the Dremel or a drill bit. Couldn't quite manage 3mm but got a nearly symmetrical 2.8mm hole. Have smoothed out the rough edges since my photo/post.
It's getting late but I might push on a bit and see how well it works tonight