Love the Seedsigner as makes setting up multisig a breeze. They complain that it's stateless like that's a bad thing. Not sure I'll ever need so sign such a complex100 utxo transaction though. 
nostr:npub17tyke9lkgxd98ruyeul6wt3pj3s9uxzgp9hxu5tsenjmweue6sqq4y3mgl