An 1 3/4" limb width sounds about right. If you're not going to recurve or flip the tips, I would only parallel the sides of the limbs out 6" from the fades and then taper to the tips. This design, IMO, will allow more "meat" mid-limb over the parallel design, reducing a lot more limb vibrations. Important for bows of this length I think.
And with a retangular handle, and using a pryamid limb design, I think it best to spread out inner limb strain by that "6" out from the fades" I mentioned above.......Art