It looks like Orucase actually makes the larger cases to order anyway, so I'd need the specific bag. I was looking at a used one, but the owner gave me a wild number and the price didn't move where I needed it to. I ended ordering a Post Carry.
I've got a friend's unused case here the "Pro" / "Team" one sold under many names (see example below), which is actually quiet compact but looks large, feels large, has some sketchy design details, and is heavy. I wanted to see if I could get smaller than that. The PC will save 5" in length, 4" in height, 5" in width, and ~12lb - it wont feel like much though as the hard case slim down quite a bit at the top. The thing the small bags have going for them is mail-abilty - if you can get the box dimensions below 30" tall and 10" wide, the Fedex/USP charge drops from $100/ea way to $60/ea way. Those nip tucks also make possible to get the bag in a trunk (maybe) and to travel with the fam.
On the seat mast, the seat tube is only 58cm long, so it's only 2cm longer than where a traditional flat top tube geometry bike would be (eg CAAD13 58 = 56.5; Checkpoint = 58cm). It's still a wild card with the drop stay. I've got Emonda ALR that's a notch easier to pack, but the Checkpoint has more flexibility for the SD trip with gearing for the hills, fitting for slow crusing, and tires for the soft roading.