As I have said in other threads, I have done the same with huck Norris and ratbites, just not strong enough. So far the strongest for me has been vittoria air liners. Worth the money in my book.
I will look into more psi then. I'm now waiting for the correct size air liners to arrive and will play about with pressure then, although I might not need to go to high with them in.
Just had 2 days riding in it and to answer your question, yes, you can get it into a 12 litre backpack. It is comfy and once you have it on, you will forget about it. It was around 18c, 64 f and sunny. I don't like the heat, so wouldn't be able to wear it above 20 max. But below that, it's fine.
I would be careful about huck Norris. As above, I damaged a rim with them in. I know some people swear by cush core, but I have spoken to someone who dinged a rim with one in and I also think someone from here has also done it.
Some are quite bad and I have had to learn to use my heel on one side and foot on the other and bounce on the wheel. It can take a bit of time. Might be worth using some grease or soap round the bead, but I have not tried it yet.
This has been a big thing with me over the last few months. First off, I tried huck Norris in 2.8 minions and damaged a rim beyond repair. Next tried magic Mary's 2.8 with ratbite and another damaged rim and then tried magic Mary's with vittoria air liners and the tread split and lost all the...
Forgot to say that I was given a shop motor, whilst Madison sourced a new one and that would have never happened if I bought from another country. Turns out the next lot of new Shimano motors are now not due till Nov.
Have bought a canyon push bike with no probs, but after all the warranty issues I have had with the e bikes that I have luckily bought locally, I would never go near one from outside the UK.
Just got magic mary 2.6 dh s, today and will run them on spare wheels with tubes to see what happens before I commit to air liners and muc off sealant.