What is that sub-floor? Looks like you may have converted an old barn or dwelling..?BKs have been known to quickly plug the combustor with fly ash when draft is too strong; I would install one fllue damper, maybe two.
With that moisture content, you are very close to the equilibrium moisture content in your climate. To get an accurate moisture content reading, take several big splits inside for a couple days to get them to room temp, re-split and test in the center of the fresh faces. 18% is good-burning wood.
Yeah, you have to burn in the load a bit to get enough wood gassing so that the cat has something to burn when you close the bypass. As long as you don't have the air wide open, with a roaring fire, you shouldn't hurt the stove at all. Moderation is the key.
Depending on what specie of "hardwood" you have, you might be able to stack some splits in the basement with a fan blowing on them. I got some White Ash from 25% down to 20% in a couple weeks doing that. Splits weren't big, though..
If the log load you got was from live trees, not much hope to get it dry this winter. You might do better with some <8" dead trees with the bark falling off..those will be close to dry.
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So who is serenading you on the banjo, as you sit and gaze at the fire?