Why not encrypt it on your throw away USB stick OS? If you move the PDF unencrypted to a different machine it make no sense to set up the USB stick OS in the first place as it offers you no additional security.


Yes, even on low entropy systems (e.g. new OS on SSD/USB stick). The mouse movements required at the start provide enough entropy to make the key generation random.


Yes, if you are careful. More below.


The "problem" with spending paper wallet funds are the software you use to do so. If you have 7 bitcoins received to a paperwallet, these 7 bitcoins are considered one or more inputs you can spend. Lets assume for simplicity you have only one input. You can think of it like a 7BTC bill or a lump of gold (I will go with the gold for this example). If you want to spend the 7 BTC lump you have to melt it down and create pieces of lesser value. Different wallets do this differently. Some would send the 5 BTC you want to keep (assuming no fee for simplicity) back to the address you previously had the 7 BTC on. Some would create an entirely new address for this. Its best that you prepare another paperwallet and manually send the lump you want to keep to it.

E.g. you have 7 BTC and want to send 2 BTC to Alice while keeping the remaining 5 BTC. You use the funds from your old paper wallet to create a TX that sends 2 BTC to 1ALICEvanity and 4.9998 BTC to 1myNEWpaperWALLET the remaining 0.0002 is used as fee.

I already do this on my windows computer. I simply have several paper wallets stored in a zip file and with very strong encryption. Passphrase is a combination of 50 characters, which I find to be strong enough. And all this sits in my USB drives offline together with my wallet.dat backups.

If you put it in a drawer, paper may survive longer than USB, statistically.
And checking or xeroxing paper has less security issues than reading or duplicating an USB stick. This is an operation you may have to do from time to tims.

Unless it has changed from what I remember is that Mycelium has a "sweep paper wallet" feature.
Using this feature is an easy and safe way to move the btc from your paper wallet.
Just sweep the lot, make the transaction you want using the Mycelium wallet and then send the change back to a new paper wallet you have created.

Splitting the btc into different wallets and addresses is a good idea but 30% online would be too much for me.
Its so easy to access cold storage now that I would never keep more that 5-10% online, why even give hackers a chance, you will regret it later.

If it's in an offline storage, such as a pendrive or such, I don't see any problem.

It's not a bad idea to print out a paper wallet in addition to saving the pdf file of your private keys in a safe location just in case. You can laminate the paper to make it withstand water and moisture and you never know you may one day need it to recover your funds if you lose your other copies because any electronic equipment may fail and paper if taken proper care of can last a very long time.

i have printed once but i moved the coins (spent) and now i am doing something similar only because i don't have a printer and i don't want to use a public one.

the problem here is that all the electronic devices can fail, there are a lot of reasons for that like device malfunction or bad sectors than can make the file inaccessible.

so i am keeping it in multiple places until i find a better solution!

It is how most clients/chain explorers display the transaction. Since the ~5BTC is obviously the change, there is no need for the client/explorer to display it as a new transaction that was sent to the address.
I am not particularly sure. I believe PDFtk[1] can help.
I'm not sure about how safe it is. However, it is a better choice to use Electrum as a offline wallet generally.[2]

[1] https://www.pdflabs.com/docs/pdftk-man-page/
[2] http://docs.electrum.org/en/latest/coldstorage.html