Need tuning help on 340

I'm not seeing detonation where it now is. I'm down about 3-4* from when it was.

Timing for total I've revved quite a ways past where the timing stopped advancing to get a reading.
(I have balancer that is degreed all the way around, and I have checked accuracy against TDC with a dial indicator.)

But I can't see any color at the base of the porcelain. (with LED otoscope) So I need to fatten the secondaries another step. (I guess what messes with my mind, is that the motor would want 2 steps lean in primaries from Edelbrock's "stock" and 2-3 steps rich in secondaries!)

As to plug temperature, I've run the Autolite 63's for a good bit of testing and see about 4 threads darkened, meaning I'm hot on the plug? The BP8ES plugs should be 2 steps colder so I'm thinking they should be OK to run for now?