Thanks, yes I agree about the virgins that might say this are incorrect.
So i dont have a cold wallet or airgapped wallet really.



I don't know why that is. Sorry, can't help you there.

It seem to be because too many inputs and I have to use coin control
To make less inputs ifI can work out how. Then the qr code will work.


I don't know why you would go through this trouble of setting up a third device and testing the transactions like you are planning. What do you expect will happen if you don't carry out those tests

I was a little bit worried if there was a malware lurking on the old laptop or if I did put one there with the usb stick by mistake.
Then I could be shown in the preview what looked to be a good transaction and I click sign. Then export the qr code but actually it was a qr code sending my bitcoins to a hacker. It is hard to see what is inside that qr code. I would think the watch only wallet could reveal it was a bad qr but maybe it would send or something would be revealed in that QR that was now getting to the internet.

So I thought maybe load that qr code with the signed tx into a 3rd offline machine with electrum and make sure the preview looked good.
Then if that looked okay then load it to the watch only and send it.

It could be unnecessary but only takes one second to scan that qr to the 3rd offline machine.

Or rather I might then use the watch only to see the hex of that qr code and send that hex with bitcoin core full node.

When people describe how to make a totally safe airgapped wallet from scratch perfectly it seems beyond my skills.
Even a brand new laptop they say sanitize the bios, remove wireless, make sure install totally safe and checked operating system again without usb or some internet seems impossible to me. Then all the new softwares or making my own private keys without any software like bitcoin core. I thought get a trezor or cold card but I still have to get the coins off that old laptop and sent to a trezor.
Then some people they dont like hardware wallets for various reasons, some which do make some sense.

  I think I will make more mistakes than just maroon this old machine  and try to limit anything on or off except qr codes and the odd input with usb where qr code is overloaded. Once I learn to