Good Morning Happy Good Friday, Happy Easter and Happy Passover to all

I would like to strip piece pinwheel blocks for a baby quilt I am making but can't figure out the size of strips I need to make a 6 inch finished pinwheel block (my alternate blocks are 6 1/2 unfinished) I've tried net searching and most of the info is for individual squares and I've gone through half my FMQ practice muslin stash trying to figure it out, can someone help me PLEASE !!!!!!

Thank you