Thermoquad question

For anyone who might enjoy thinking about TQ's a bit...

I have everything pretty dialed in, and TQ sorted to the point of good looking plugs and good numbers in general on my A/F meter. (Timing on the 340 is at 18/38 which gives best 1/4 MPH and the ignition curve is pretty worked out as well.) Mostly it's running clean, strong, no bog, etc. Jets .101/.149 (need a bit smaller for WOT)

Now the air door spring is at 2-1/2, the rods up 1-1/2 turns, idles screws now out 1-1/2 with the fall air.

Here are the symptons:
1) I get a new very slight stumble/falter with snapping the throttle at idle or very low rpm.
2) Idle mix shows mid 14s A/F BUT occasionally. all of a sudden, shows 16-17 on the meter! (I'm OK with leaner idle, but not sure why it would jump back and forth.)
3) It was acting very good for months, now with the slightest throttle (added vacuum) the mix drops to 10-11:1, vs the previous 15.5 on light acceleration. (13.5 on decceleration)
4) low rpm cruise is a bit rich at 13.5 when it was at 14-15.

What has changed???
To be clear, the main issues are the 10-11 on light throttle and that initial falter/stumble.
My first response would be be to lean out the idle more, or to drop the rods more, but either of these makes that initial stumble worse.
I had for a while removed the spring under the rod piston as some had suggested but it would get too lean with part throttle so put the stock spring back in and was working fine. What has changed????? I could remove the spring again, or use a lighter on, but that seems like it would make the stumble worse.

At this point my brain gets scrambled, so I thought I'd ask you guys.