Kiln drying is better and faster.

Putting it in an enclosed space to get the MC lower should work with proper ventilation but the major issue is that it might have already dried too fast and checked.

You can cut a small piece of wood. weight it (you need at least a postal type scale) and then dry it in the oven and weigh it again.

The weight loss is the water.

The percent is defined as the water lost divided by the dry weight of the wood.

It can be over 100% for green wood since the water can weigh more than the dry wood.

Something didn't seem right when I came back in eight or nine months to take it to the planer. Seemed to be a dampness about it. As I worked down into the stack, my worry turned to horror as board after board had turned into mold farms, with slimy discoloration all over all but the ends.

I forget how much I lost, but the moral is keep your eye on it once in a while. Don't make the foolish mistake I did ignoring the importance of proper circulation.