Pack is almost perfect but what I would change would be foam in the shoulder pads, I doubled up the 3d Mesh. It tends to twist and bunch up more without it. Drop the Beastee rings and just use webbing on the attachment points.
What worked perfectly:
4" extra width on the mesh then box pleated is right on.
Decreasing the shock cord 1/2" from the width of the pack gives it enough snapback.
1" seam allowance works great, cut the fabric inside down to 1/4-1/2", roll the allowance over inside, sew, add grosgrain, sew, is the way to go. Works great.
Lineloc 3 WSR Buckle system is great.