I don't touch the checkering at all when I'm doing the multiple coats on any of the stocks that has it. I'll mask it off if I have to before I start.
Carefully, I'll use a soft kids tooth brush for the checkering with the final coat...gets into the pattern real nice and no excess runnin around. A few double pointed tooth picks to clean around the master lines of the checkering when the T Oil is still wet is the finishing touch...unless the stock requires a dull / satin look...then that's the finale !