Radio is one of the ones that really benefits from the space.
I thought micro's were 1.6mm or smaller and 5 wraps or less. At least that was the understanding I had a couple of years ago.
Ok, you've convinced me to try a little spacing with the gunkers next wicking. I already re-wicked Radio, hitting really well right now, and I only have about 432 feet of Rayon left, barely enough for 5000 more wicks.
And your number sounds more correct than my 2mm, though it might be 1/16" I'm remembering, pretty much the same. Not sure about wraps being in the equation, though.