Well I decided to go straight to the source and present my concern to Red Oxx. I spoke with an exceptionally kind and helpful lady there who said that the Air Boss's "sweet spot" really takes affect at around 3 day trips or more. Based on the travel that I described to her she suggested that I look at the Skytrain. After looking at the specs I don't think this would be a good fit as I really do need that center section for laptop and other work-related gear.

Anyway, I'm now leaning towards the Tri-Star, as it's just a little bit smaller.

Truly I think the Western Flyer would probably meet the needs for half of my trips but again just don't want to get in a situation where I need more bag. For example I do work outside and so in the winter need to pack heavier clothes, etc.

Thanks again to all for the feedback, much appreciated.