font weights problem

Hi, first many thanks for your plugin!
I use Playfair Display but I can’t have weights I need. Seems there is just regular “bold”. in json file i can see all weights but compared to google font i have just regular and a bold that seems to be 600. Even if I choose 700 or 800. Did I miss something ?
I I check header font link I don’t see any weight spécification : https://fonts.googleapis.com/css?family=Open+Sans%3A400%2C700%7CPlayfair+Display&ver=6….

Last point is it possible to ass swap to header font link ?

Thanks for your answers !
Best regards