Hello all,
I need to install a new window (2’w x 3’h) in about the middle of the wall shown in the pic.  It’s an exterior 2×4 wall with let in bracing, no plywood sheathing, 1″ continuous foam exterior insulation, and vertical channel rustic cedar siding installed over horizontal 1x strapping. Single story house in North East Ohio.

Since I will need to remove a section of the existing corner bracing, my question is how to replace the racking resistance provided by the bracing. 

My thought is to let in new diagonal bracing (on the inside)  below the window framing spanning as many studs as possible.

Is this a reasonable approach, or is there a better way?