So about that IKEA storage bag, the DIMPA↑,
I received comments from two knowledgeable folks
so I thought I'd share what they said.

First, apparently it's also well-known in the community
as a storage bag for Brompton bikes.
One commenter called it a "bikepacking bag,"
but I'm going to stick with "storage bag"
to avoid stirring up the "no true bikepacking
except with a proper bag" crowd.
If you don't want to get called out by the
"bikepacking police" on social media,
better not post photos of DIY bikepacking setups.
Personally though, as long as your bike is fully covered
and you're not bothering other people with protruding parts
or oil stains,
I think it's fine either way.

The second thing was about how I recently wrote
that cyclocross wheels with 32C knobby tires
fit perfectly in it—that's the second image in that post—
and apparently if you don't mind fitting just one wheel,
wheels with tires like 29×2.6 or
26×4.8 will also fit.

Thanks for the comments, everyone.