Barbequed Buttermilk Chicken

Tried another one from Chef John.
 
https://youtu.be/WW0qgxHlE4Q
 
Started the marinade last night, mowed lawn and trimmed my front trees this morning (cloudy and cool, nice!) and let the Large come up to temp while I took a shower.  Chef John cooks on an Egg too, but I went raised indirect, 400º, hoping for a little bit less burning.  Came out well:
 
 
 
Before getting my Egg the only chicken I ever cooked was skinless, boneless breasts or thighs, and usually in a wok.  Anymore I can usually carve up a whole raw chicken, or cooked spatchcock chicken, but this is the first time I tried carving cooked half-chickens; let's say I butchered it, and not in a good way.    
 
Damn it was good.  I usually get 3 or 4 meals out of one chicken (especially a 5-pounder) but the first half pretty much disappeared, and I'm due for a nap.  I also left the wing tips and flappers on, unlike CM.  I will be making this again, but maybe cutting up the bird into parts before cooking.
 
And a question:  the Commissary had three different brands of buttermilk, but they were all marked "Lo Fat"; is that the only way buttermilk is available?