Nick W.

I assume you're already collecting annecdotal feedback from managers on what their team members are good at if their a small team? Anecdotes could be just as revealing and valuable as the data itself. Otherwise, I assume you're using an outreach tool and/or CRM? If not, what do you use to track sales today?

I think the first thing you would need to do is identify the point of greatest friction for that middle 70% as compared to the top performers, wether it's converting first meetings, converting demos, or another sales stage. That way you have an idea of what the highest impact are to train might be and you can focus on that. Have you tried this already?