I am working on a small frame using spruce. I have built one frame previously using pine beetle kill which was DRY (less than my moisture meter reads.... 8%) and the spruce I have now is quite wet (22%). Just wondering if the tenons will get loose as the wood dries? I live in northern Alberta where the air is extremely dry. So far I have just been making tenons and avoiding the mortises as I am worried everything will loosen up if I make it fit snug while it is wet. Any thoughts or experiences? Thanks

M&T thicknesses will shrink together.The length of mortise will not change. The depth of the mortise will decrease. The length of the tenons will remain unchanged.
I cut all joints in fresh cut White Pine.There is rarely an issue with frames becoming loose.

With spruce I have see excess twist that has cause a little grief, usually it is not a problem a little trimming will cure.