Question:
Since I am not going to donate the entire BTC funds to this foundation I am wondering what will happen with the rest if I am
going to shutdown Tails..
Are the non spent/donated funds lost this way? What precedure do you recomend?
I will start with something a bit deeper: your funds are not on Tails and not even in the wallet. The easier to understand is that the funds are on the blockchain.
The wallet only offers the keys to tell the blockchain that those funds are yours and you are allowed/entitled to spend them.
Keep in mind that the correct way to spend your funds with Tails (as cold storage) are:
* recover your wallet on Tails WITHOUT INTERNET. I usually recommend also no persistency.
* if your wallet is recovered from seed, then copy the master
public key
Note: you will never see funds in your wallet on Tails.
On another system or after a reboot make a
watch only wallet off that master public key. This will be on a system with internet. Here you'll see the amount of funds, here you'll make the transaction.
You will see on Electrum that it will send the donation amount to the donation address and the rest to another address. Normally that another address is a CHANGE ADDRESS in YOUR WALLET. Unless it's a counterfeit Electrum or you have some odd settings, this is a normal behavior.
If you don't trust this an want control on where to send the change, that's also possible, just ask and people will tell.
Now this transaction has to get to that Tails (so extra USB maybe), get signed, get back to the online system and broadcasted.
Remember, tails remains offline all the time.
Sorry if you knew all this.
So, the change will return to your change address, so back to your wallet.
So, since the money are not actually in the wallet, it doesn't matter if Tails is started or not.