boy., i have three different measurements doing this. First says1" for front, 2" for back.
Second one says Flange 1 3/4" for inside fold and 1 1/2" for front.
Third says (McCalls) binding 1 1/4" color and for flange 1 1/2".
sew, press seam toward binding color. fold after pressing. place faux side down on backing and sew and flip to front. then finish.
so what ever way you work it, test first before sewing on....
have fun and good luck. I only did this once and it's been long ago.