Good idea, thanks for sharing. So I set up an MX record (on Route 53) to point to Fastmail and also set up DKIM by adding several CNAME records for fm1._domaink

Good idea, thanks for sharing. So I set up an MX record (on Route 53) to point to Fastmail and also set up DKIM by adding several CNAME records for fm1._domainkey.mydomain.com. FM confirmed pretty quick that those changes were made. The last bit is SPF config. I added a TXT record as per the instructions, but I keep rechecking with FM and it's not verified. Emails from FM currently show up as being sent "via messagingengine.com". Any ideas - do I just need to wait?