Every month, we're always refining who could use our product. Our journey on who would be an ideal customer changed almost every month. Here's our persona journey:
October 2018 - October 2019: Anyone with a website (especially startup websites).
November 2019: All small businesses making $1M or less.
December 2019: All small ecommerce sites
January 2020: Web professionals who make websites and businesses that use platforms to make money (e.g.: WordPress, SquareSpace, Shopify).
Every time we changed updated our persona we narrowed down when a certain message hit.
It's a lot of testing but if you validate through 3-4 different channels, you can be confident you're speaking to the right person.