Thanks to the dangerous combination of boredom, curiosity, and impatience, I decided to string up three 1Ω resistors while waiting for the 3.3s to arrive, and test with that. But it quickly got out of hand as I measured 1, 2, 3...6, 10, and 20 Ω additions to the crossover, just to see if something awful would happen. As it turns out, one of my A130s ("B") benefits a good bit more from the added parallel resistance than the other ("A")! Overall what this is telling me is that the value isn't terribly critical, and with QC/variance between speakers some experimentation may be worth considering.
Full spread of resistance values and their changes that were taken for each speaker:
And before/after on values that I will likely aim for with the final mod:
As an added bonus, the THD also flattened out for the effective range (particularly 1kHz+), although the difference between 0.4% and 0.3% at 3.5kHz is probably nothing to get too excited about. Especially considering that was on the extreme end at 20Ω. I just was worried that it may add some weird effects.
One tweeter remains a bit hot though so I'll work on attenuating it next. Interesting that the 15.5kHz peak is pretty much bang on between the two while anything below is consistently a bit off (1.3dB from 5-14kHz). After addressing that I'll finally feel comfortable enough to leave them alone and just enjoy them... I hope.