You have picked out fabulous fabrics for your GFG quilt! I don't know how many it will take.
I have a GFG quilt that a great-aunt made from the 1940-50's and her hexies are 1 1/4" finished size. She had 9 rosettes rows across and 11 rossette rows down and used 1/2 rosette on the edge of the rows. My quilt measures appr. 85" x 90". I hope this helps!
Quilt showing the edges w/half rosettes
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I have this quilt folded and hanging in my sewing room
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