Oh well, hard to argue with simplicity.
A rolling we shall go...
Actually a little hard to roll because it's practically airtight. My buckles for the strap ends may be arriving relatively late in the afternoon, may have to just sew some loops in the webbing and cinch in down with some rope to do a loaded test ride up the local trail
Uncertain yet if I'm going to need some internal straps to hold the cutting board in the back, but can sew those to the exposed inside seam allowances (lazy) if I need to. What I do need to do is go put some painters tape on the rack and carefully mark where the trunk bag attachments fall and where these will so that I can deconflict them.
Overall I think the sizing is definitely small, but two of these and the trunk bag should be enough for the pending trip, and I can do something larger later and relegate these for odds and ends on local family rides, or try to convert them to front mounting on the fork braze-ons.
Right now I still have enough fabric on hand to make two more in a zip style, but probably not a second roller and two zip style, so I need to test this a bit and decide it's going to work before I cut out a second of this style.