The Westjet website (https://www.westjet.com/en-ca/flights/fees#selection) gives pretty unhelpful ranges for seat selection fees (5-250 CAD for exit row for example). Is there a way to get more specific information?

I am looking to book some DL code WJ operated flights and I guess I pay whatever the WJ seat assignment fee is since DL tells me to go to WJ for seat assignment. I want to understand how much this is before I decide between booking DL code and WJ Econo or EconoFlex.