"Use side compression straps, rather than elastic cords, to better compress the pack"
What if, instead of 'straps', Joe used inelastic cordage, like his z-line or another cord typically used for guylines?
That way, it wouldn't stretch, but would still be sublimely light and take exactly the same amount of work in making the pack. Also, it's mod anybody could do at home.
I'm looking at this pack and thinking that the extra volume would be fine if it had the wrap-around compression options that modern Golite Jams have; what if the guyline cord was strung through the back mesh, though, so the pocket could be filled and accessed even while the main body of the pack was thoroughly compressed on three sides? I haven't many miles of experience with UL packs yet, but that designs seems like money to me.