Fitness as a percentage

This has been asked before but I can’t find a solution…

I’m colour blind and I’m really struggling with the heart that indicates the fitness so I’ve been trying to get it as a percentage. 
 

I tried the Priisek Dark skin but I couldn’t work how to change it 🙈

Can anyone recommend a way to change it or recommend another skin / way to have the old style where it’s displayed as a number?