How to find people for a S4S?

Hey guys,

I will reach 10K on my fitness account in the next few days and, reaching this milestone, I would be interested in starting S4S. My question is : do you have a specific technic to find accounts in the same niche and in the same range of followers as you ? To me it looks quite hard and ineffective to go through a list of a few thousand people in hope to find someone who is approximately at 10K followers. If I could find something like 50-100 accounts like mine I would email them…

How to find people for a S4S?