Hi! I have a quick story that supports your plan to test elements. When I visited Nestle HQ at my last job, the presenter shared a story about their anthropology department. Specifically, they asked consumers from various parts of the globe to describe health. One trend they noticed is that different cultures stressed different functionality - the US tended towards strength, another culture towards the circulatory system (and having all things work together), and another towards the brain. they had been stressing growth, but needed to narrow messaging based upon beliefs. In this case, sharing how ones body would function well together was 100% the right message for one group and 100% an ineffective message for another. This realization helped them tweak messaging and, revitalize some somewhat products. I don't think you can go wrong with asking for input as long as you have the time.
I'm all for putting messaging in front of potential members or, if possible, holding a focus group to hear how they describe success (in the above story, health). This may lead to a larger takeaway for key messaging and, at least, help you confirm approaches.