content: Still have my old gmail for "business critical" stuff while I figure this stuff out. Last time I managed an email server was pre-DKIM and SPF, so it's a bit of a learning experience. Though as you say, I have noticed that even despite correct PTR, SPF and DKIM records, gmail does chuck some of my test-mails into "Spam" for some reason; could be the fact they are test emails of course. If it turns out to be too much of a hassle I will abandon it, but for now, as I said,  it has been a great learning experience.