A couple of comments have reminded me of something I should have mentioned and thought of.
A French seam and faux flat felled works only if you are dealing with a light, shirt weight fabric. Anything heavier and the traditional flat felled would be the seam of choice.
I had no problem doing the topstitched French seam thing with my current cotton broadcloth but would go back and use a straight up flat felled when I am working on my pique shirts.
Appreciate the reminder.