Currently, the GUI is useless in signing transactions offline due to a known and open window-scaling issue in some devices with smaller/lower-res screen (at least for me anyway) wherein the "Advanced Options" buttons at the bottom are cut off and inaccessible (specifically the "Sign tx file" button). It's supposed to be fixed in the next release but in the meantime, what are the steps to sign transactions offline using CLI (reluctantly due to CLI phobia but I'm left with no choice).
See:
https://monero.stackexchange.com/questions/2868/is-there-any-way-to-construct-a-transaction-manually/2916
To create a view wallet, one has to add the --generate-from-view-key
On Windows make sure to launch it from the command line. Go to the folder monero-wallet-cli is located and make sure your cursor isn't located on any of the files. Subsequently do SHIFT + right click and it will give you an option to "Open command window here". Lastly, type the following command:
monero-wallet-cli --generate-from-view-key
On Linux and Mac OS X you should use the terminal to launch monero-wallet-cli. Note that this has to be done from the directory monero-wallet-cli is located in. The command is as follows:
./monero-wallet-cli --generate-from-view-key
I'm already good with creating an unsigned transaction with the online view-only wallet in GUI which runs on a desktop with a rather large monitor (not affected by the scaling issue). I just need to know the specific CLI strings/args to sign the transaction with the cold wallet on the offline device using CLI (and subsequently export it back to the online GUI wallet for broadcasting) since my offline GUI is unusable due the the aforementioned scaling issue. Thanks!
You can still use the guide I linked. For every step that uses the "watch wallet" you use the GUI, whereas for every step that uses the "cold wallet" you use the CLI. For example, step 1 of the guide is as follows:
Thus, for this step you use the GUI.
Anoter example, step 3 is as follows:
Thus, for this step you use the CLI.