Dan...I really enjoyed those pics...great work...it looks to be more wide open than I first thought it was.
Gary said that his is more closed in and hasn't noticed any drop in ventilation so that's good and better than I first thought as coals need to draw up air for burning and to provide that convection oven effect when lid is closed.
I was thinking however, if you were going to close in the other side (eg; the more open side) you might be better to maybe use some kind of sliding or concertina door set-up as you, family or any guests walking around the grill-station will be bangin' their legs up on the outward open doors if they are open to provide ventilation/air......this is coming from somebody (me) who has banged his leg up on many open doors hehehe
Cheers
Davo