I've looked at a few packing threads for beer but had not seen this one. I was looking for some material to double box my first trade when I found old egg cartons and drink trays work great. Ask for one every time you get coffee.
Man that box is 15 years old. Just look at the computer on the box....as for the samosas not a coconut fan. Frozen thin mints , yep.
Sooner or later you will notice that everything you are about to discard or recycle becomes one of two things. Good for packing material, not good for packing material.
Top marks to you for simplicity and economy. I took a different route....I built a mobile growler bomb shelter. Damn the cost, damn the ozone layer.
It's spray foam - the type you would use to seal around a door or window. It took about 6 cans if I recall correctly. Spray a can or two at a time and then give it a few hours to fully expand and cure. I bought a concrete tube and cut it into thirds to make the canisters you mentioned.
actual concrete would have been better... shipping's a little higher, but fedex can't drop what they can't lift.
If I take it you would use this in a bomber for bomber trade. "I'll send you yours, send mine back in the box"? Very cool idea. If you really wanted to get secure you could use an old bomber an put it in the tube upside down to make a molded plug for the neck. Then just stick em over the top to keep the bottle from rocking.
Maybe the pic doesn't give it the appropriate scale. Those tubes are 8 or 10 inches in diameter (can't honestly recall which it is). Bombers would be lost in there. I made it to ship three 64 oz growlers in a GIF earlier this year - each in a cozy bed of bubble wrap. You would not believe how many often a wife will scoff and roll her eyes when you A) mention that you have a plan to make a custom beer shipping box and B) set off to the garage to actually make said custom box.