This is the best option. If you already have a Trezor set up, it is very easy to import your wallets on to Electrum. Just download the latest version, set up a new wallet, select "Standard wallet" then "Use a hardware device", select your Trezor, and select native SegWit. Once it syncs, all the addresses your Trezor usually unlocks on your Trezor Wallet will be available on Electrum. You can sign a message in there, and it is easy for anyone else to verify.