How are foam cores shaped for tapered and swept back wings?
I'll assume you're already researched the methods for hot wire cutting foam blocks in the Rutan moldless method and are familiar the hot wire tool and airfoil templates you make and the template cutting process.
You can do it two ways; make hotwire templates with the longitudinal axis airfoil contour (the stretched airfoil shape resulting from the sweep) to stick on the end of the foam blocks that you have already truncated with the 10 degree sweep, or make the templates to the airfoil profile perpendicular to the mean chord line, stick them on to the blocks with square ends, and truncate them to the 10 degrees sweep angle after you've cut them out.