I have the same issue, f2a electrum wallet.

trezor have a new solution for this, didn't check it, I wonder if it will work for the f2a multisig

https://blog.trezor.io/claim-bitcoin-gold-bgold-btg-f66969e7f2c0


I will check it tonight and update.

* wallet new version to support this is still in beta, so I will wait few more days.