I answered this in a similar post - see it here: https://sharebird.com/can-you-outline-the-best-structure-and-format-for-user-personas-that-are-useful-across-the-org
Sure do! I like to start with some qualitative research first to help get at any nuances in messaging, especially across different audience segments. Then, run a survey (max diff is a great technique) to understand what resonates most with your different segments. If you also have the budget and/or time, running your messaging by focus groups is another good option, so you can get a deeper understanding of their reactions and sentiment.
I would start with getting information from Sales first. At Square, I rely very strongly on Account Managers to get a sense for the needs and attitudes of larger merchants. I'll talk to them directly first and then will try to partner up with them on specific conversations to close very specific knowledge gaps. Try to coordinate with your Sales / AM counterparts to make the 30 - 45 minute call with customers productive for everyone.