This is great, I've also tried it with a cut up chicken but it didn't get as crispy. Last time I tried it with a beer can roaster stand but didn't arrange it right so the breast was not as crisp, I will arrange it better next time. I also use a large zip lock bag instead of a bowl, just don't let the squimish see it in the fridge.
My chickens were 3 lbs each so used 3/4 cup dijon, minced half the garlic cloves and loved the fact that I was able to use all fresh herbs from my kitchen counter planter. I thought the mustard mixture was more than needed but it all turned out wonderful. Perhaps next time will try only using half the amount or double up the amount of chicken. You are absolutely right - "It's all good!"