I think you've got something here. Values 0 to 10 should be assigned according to vintage Albion performances. Trossard Liverpool away was a 10. No away player scores a hat trick at Anfield let alone a BHAFC one. It's a 10.
Trossard as sub against Charlton, however, was a 0. I've seen statues move more then he missed a pen
I'd struggle to get values solely with Trossard from 1-9 though.
That will work.
Another example of a 10 for the new scale … Mac against Manure a year ago. He ground them into the dirt with skill and tenacity, they ended up hacking away at him, capped with the wonderful pressure penalty.