Private domain registrations is not recommended, But this is well down the list of things that will get you automatically marked as spam.
Your ISP will let you send so many emails per minute over their connection. 20 seems to be a safe bet for both your ISP and the servers that you will be sending too.
Every email campaign that you send will get scanned for a spam rating, If your rating is too high then you will be flagged as spam.
I would suggest that you send a email template to
spamcheck@sitesell.net make sure to put TEST in the email subject. The Email that you just sent will bounce back to the email address that you sent it from giving you a spam rating.
The list goes on and on, But I hope this helps for now