I had the same questions and found this excellent note by nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z He compares different relay types and includes his relay setup for Amethyst.
nostr:naddr1qvzqqqr4gupzq3svyhng9ld8sv44950j957j9vchdktj7cxumsep9mvvjthc2pjuqq9hyetvv9uj6um9w36hq9mgjg8