A community member via Intercom asked how to deploy ERC777 with GSN.
There is a Simple ERC777 token example in the forum.
With ERC777 you need to take into account reentrancy, see Reentrancy After Istanbul
As for the GSN:
GSNv1: Use in production now (though you may want to run your own relayer on mainnet to ensure availability).
Assuming you are just getting started and depending on your development roadmap, you could look at the upcoming improvements in GSNv2. I suggest joining the OpenGSN telegram to get the latest news on GSNv2 development and timescales.
If you haven’t already, you could go through the Building a GSN-powered DApp guide for GSNv1.
You will need to devise a strategy for which GSN relayed calls you will accept (which calls you want to pay for). See: GSN Strategies.