Basic first aid supplies: A few bandages of varying sizes. 6 Aspirin, or other OTC painkiller of choice. A few alcohol pads in sealed foil packs, useful for cleaning grease off grease and grit off of the bike, and also cleaning cuts on yourself if you take a spill. 1 day supply of any prescription drugs you need to take regularly. Wrap these up in tinfoil and tuck away. It might just save your day.
Basically, you’re stuck with toggling between systems for the advantage of a few pumps, and it doesn’t seem worth it. In the original iteration of this guide, I tested 12 pumps and inflated three different tires completely full to their psi rating, and measured how many pumps it took. Yasuda did similarly for his revamped full-length exploration. That’s 36 tires, and I can guarantee there is no difference between 50 pumps and 100—it’s all terrible.
In spite of seat bags’ diminutive size, a lot of people really, really want them to accommodate more stuff. If that’s you, the medium and large seat bag (but not the small) have an extendable gill at the bottom, which you can see in the image up top. It zips open to create more room. With it unzipped, we could cram a wallet, keys, and phone inside the medium as well.
If you’re going to use the chain whip you just made, you’ll also need a way to get that cassette off. A lockring remover is a must-have; unless you use one of the shady removal methods I’ve seen on the internet—which I wouldn’t necessarily recommend unless you don’t care much about the condition of the wheel after you use them. I recommend Park Tool’s iterations here that cost about $6, but you’ll need to buy the specific one for your brand/type of cassette. (By the way, I’m assuming you already have an adjustable wrench laying around somewhere to use with this tool. If you don’t, well, you’ll need one of those too.)