Thoughts/Ideas on Using Beta Testers?

We're about to launch the RankCaddy beta (https://www.rankcaddy.io/) and I'm curious about how others have gone about this. My initial thoughts are:

• Tap into my industry contacts and invite them to test.
• Post on relevant groups I'm in to invite people.
• Get people to sign up on the homepage and then invite x amount of them.
• Offer them 6 months free for being part of the beta.

What am I missing? I thought about using something like BetaList but heard that's not quite what it used to be and also takes a long time to be approved anyway.

Is there anything else I should be doing/trying, in order to get the most of this period, before we launch to everyone?

Thanks