Are you sending real emails or emails that say nothing more than test?
Is this a newsletter that many recipients receive, some sort of transactional notification/status emails, or regular emails?
If it's a newsletter feel free to subscribe the Hotmail and Yahoo addresses I sent you.
Create the SPF record. Try another test after that DNS change is live.
What happens if you register a new Hotmail account and add it to your list of addresses?
I noticed in your test to me that you used a new From: addresses. Try using whatever the regular From: address is since it's historical reputation quality will be different than a new email address sending email. All of the tests are originating from the same IP as the regular emails, right?