My favorite recurves all have a narrow and deep profile (my top 2 are both under 1-1/2" at the fades). The limb mass is actually less in this config (twice as wide is twice as stiff, but twice as thick is 8x as stiff). You also get less wind resistance with the narrower limb (hey, it's a little more performance
) So with everything else being equal (profile, tiller, etc) the narrower limb should perform better than the wider limb.
Downside of the narrow limbs? Less lateral stability and it's more critical that the bow be layed out properly. If you have a really extreme recurve that's not lined up properly you'll likely unstring the bow at the shot! One of the bows I spoke of above has a pretty extreme profile and is around 1-3/8" at the fades and taper straight back to the tips. The tips aren't any wider than most longbows. The other bow isn't as extreme, but the tips are narrower than most longbows!
Since they have all the formulas worked out, I'd go with the 1-3/4" sticking with Bingham's plans.