Eversince blockchain.info has started a facist campaing against TOR users I've been searching for a way to store and send bitcoin to markets while staying anonymous.
Electrum has an option to connect through proxy. There are also .onion electrum servers. Setting this proxy to localhost 9050 (TOR) is enough to prevent my IP being related to the electrum wallet? Are the .onion servers safe / necessary?
I'm also open to alternatives but I haven't found many online wallets that supoort sending to multisig addresses (greenaddress.it doesn't work lately for me).
Unfortunately, electrum is not the best option for privacy at the moment. When you connect to an electrum server, you leave a "fingerprint" of all your addresses that you request info for. So if you were ever to connect to the same server outside of tor, you could leak your location information to the server.
It is possible to use electrum by using a new wallet exclusively on tor, and create a new wallet any time you need a new identity, but it's not simple and it would be easy to make mistakes.