How best to prevent being identified as SPAM and blacklisted

Hello Chris and thank you for posting about this on our forum. It is indeed of concern to many of us not to be identified as spammers, as it's hard to undo once marked.

NS Pro offers many features to avoid being marked as a spammer.
1. Email throttling. As you mentioned, email throttling is important. In essence, email throttling means sending a few emails at a time. NS Pro supports this by having an "Emails per send" field in your newsletters, that you can set to something like 240 per half hour. If you use our free cron job triggering service , NS Pro is triggered twice per hour and sends THIS amount of emails (set by the emails per send).
2. List-Unsubscribe feature. By default, all NS Pro emails contain a list-unsubscribe header that proves to email services that you are willing to make it easy to your recipients to unsubscribe if they wish to.
3. Bounce handling. If configured correctly, NS Pro can automatically handle email bounces. If you keep sending to emails that do not exist, you risk being marked as spammer.
4. DKIM support. If your email server requires from your software to set the DKIM headers, you can do so in NS Pro's component options. This is not the usual case, but some hosts, like GoDaddy, that do not allow you to directly manage your email server's DNS records, may require this.
5. In-place spam-score testing. You can test your emails' spaminess, directly from the edit newsletter page, using our affiliate service mail-tester.com.

It is our general suggestion to always send your newsletters to mail-tester.com first, and see if you can improve your score. I always send newsletters with a score of 10 out of 10, which is excellent.

Something important that NS Pro cannot control is your email content. Make sure that your emails do not include Javascript, not even onclick="" events, in case you use such things in your site articles.
In general, if you keep your content relatively small and static, you shouldn't worry about getting blacklisted.

If your server does get marked as spam, you can always use online tools for "email blacklist check" and ask for removal. Such services are usually eager to co-operate, as long as you can prove your good will.

Let me know if you have any further questions.

I understand.
If you have SPF and DKIM and pass your newsletters through mail-tester first to check your content, you will be good to go.

Let me know if you need any further assistance.