If you don’t already have confirmed business at roster publish your never going to get it. There’s simply not enough business class seats available to do that. With the introduction of A220s and E-Jets there’s a 17% reduction in business class seats available on many mainline routes.
You’re better off improving the deal you get when your given an economy seat (eg: guaranteed isle or window with spare seat next to you or $200 allowance whenever your seated in economy).