Hi @Finnahair,
Bags like the Co-Pilot and Parental Unit have enough structure from the internal compartment design that you don’t need to stiffen them, even when they are Halcyon — which is 400d unless you go far enough back to when they made a small number of Co-Pilots in 200d Halcyon bags in colors like Iberian (similarly for the original Synapse which was made in 200d Halcyon in Ultraviolet, and Iberian, as well as steel in a few batches.)
The issue of additional structural support only arises when when you have bags with essentially “bucket” designs — large contiguous volumes that maximize space without additional materials in the supporting structure — like the Maker’s Bag, or the Swift. Even then, the user may not need more support, depending on what is being carried and the reasons for selecting that bag. If the bag is mostly full, with a laptop that runs along most of the length, or if the user routinely carries stiff plastic or polyethylene folders in the back zippered pockets, there may be no need for additional pouches to “stiffen” the bag. For a Swift made of 400d Halcyon, inserting U.S. letter size folders vertically between the two clear pockets and the sides of the bag will keep the bag from sagging, even when completely empty, or when the top pockets are weighted down.
The only reason for “stiffening” the Packing Cube Shoulder Bag is because these Halcyon accessories are generally only available in 200d Halcyon, which reflects their origins as Packing Cubes (with no need for extra reinforcement if they are holding clothes). The PCSB has been extremely popular for use as a larger carrying alternative to the Side Effect and Side Kick, despite its lack of internal organization. It has only rarely been made of 400d Halcyon. The one big exception was when they ran out of their stock of 200d Halcyon due to supplier production delays, and offered the Packing Cube Shoulder Bag, Packing Cube Backpacks, Travel Trays and Shop Bags in 400d Halcyon. (We were a bit worried about the reality of this offer since Darcy posted this on April Fool’s Day.) So, the Packing Cube Shoulder Bag in my picture is 400d Steel Halcyon.
Most people have a hard time envisioning the texture and feel of 400d Halcyon if they’ve only experienced 200d Halcyon accessories. My Synapse 25 EDC was made in the very first production batch of the S25, and is Steel 400d Halcyon with a Wasabi 200d lining.
HTH
moriond