Don't ease the box, just the tenon. I think if you ease the box there is more of a chance that it will look like a gap to the layman.
Eased tenons aren't just G&G, that's been going on longer than those dudes were alive.
Just my opinion which is only worth the price you paid for it.
Looking exceptional brother!
Lincoln - "Give me six hours to chop down a tree and I will spend the first four sharpening the axe." Dave in AZ