Hello. I am going to be putting some new construction windows in an old house. I will be removing the aluminum window frames and wood frame down to the rough opening. The nailing flange in the old windows is nailed directly to the studs with the siding overlapping the flange. There is no plywood sheathing. My questions is: what is the best way to install the new windows? Should I nail the new flange to the siding and flash over the top? Or should i cut back some of the siding and nail the flange to the studs as was done previously? Should i try to remove the siding and replace over the flange? Thanks.