If you are gluing up from plywood, you can add something in between sheets to make a full 1 .75"
Lots of guys are using LVL, comes in exact widths form the lumberyard.
If you have a 1 3/4 strip to glue to the face of the form, you can do that and then bondo under the lip so the glue doesn't hang there when removing bow from form.
Probably many other ways to skin this cat also!.