Just an update: I received the fridge the other day. I immediately put the transit cover on and threw it in the truck for a test fit. I can say unequivocally that I am glad I listened to [MENTION=65614]Antman[/MENTION] and others about the 50 and I post this in case anyone else stumbles by with the same question.
First, we are a family of 4 that usually does weekend trips, maybe out to a week. I am confident I will be able to pack this 50 for those trips. I may have to cycle some drinks in and out , but that is no big deal and I had always assumed that with the 50 or 63.
Just as importantly is the fitment in the cargo area. My kids love and constantly utilize the recline feature on the rear seats. At first I put the fridge on the passenger side, behind the 60% side of the bench seat. Realizing that the seat would no longer fully recline I moved it over to the driver side, the 40% side. It fit against the 40 seat perfectly. So Now the 60 side can lean back fully and the 40 side can lean back halfway (first click). This is perfect. With the 40 seat leaned back halfway the fridge lines up exactly with the plastic lip of the cargo tray. Perfect in both directions. Had the fridge been wider I would have lost full recline on the 60. Had it been longer it would have gone further than the carpet and sat on the trays plastic lip (which would have unreasonably bothered me). As it is it is a perfect fit, like it was made for that spot. Plenty of space on the inside, perfect fit on the outside, I am super happy with my choice considering I had really been leaning towards the 63.
Thanks to all for the tips and advice.