If you weigh the top for a classical guitar before putting on the bracing and after, you'll find that the bracing is not all that much of the total mass. I'm not as good about keeping track of that as I should be, but that is, in part, because I've come to the conclusion that the bracing is really the place to try to save weight; it's the to. I did quickly pull records of a few guitars I've made over the past several years (there's nothing so useful as a file cabinet!), and although I kept the records in different ways, there's some useful information.
The most useful numbers for this discussion come from my #90. pretty much a 'straight up' classical in Indian rosewood and European spruce. The overall weight of the completed top was 174 grams. Of that, the upper transverse brace, and associated bracing (such as the sound hole patch) weighed 20 grams, and the fans in the lower bout weighed 11.5 grams.
The top for my #102, in walnut and redwood, weighed 142 grams when it was taken to thickness and trimmed to shape, and 174 grams with all the bracing. #118, cedar and Morado, had a 'bare' top that weighed 131 grams, and the final weight was 167 grams.
Bridges tend to come in a little above 20 grams, so the bridge weighs almost as much as all of the bracing put together. You can't do much to reduce the mass of the upper transverse brace, and it's not really worth trying anyway: that's structural, and on most classical guitars the soundboard below the waist bar is what's producing most of the sound.
Mote that I 'tune' my tops off the guitar, and try hard to avoid removing any material once I've assembled it. These weights are within a few grams of 'actual'. In the tuning process I sometimes (not often enough...) keep track of how much mass I've taken off the braces. It's usually not much more than about 5-10 grams. start to finish. This make a big difference in the 'tap tones' of the plate, and (I hoe) accounts for some part of whatever success I've enjoyed.
Wright's computer model found that reducing the mass of the top by 30% would produce a useful increase in sound output; something people can hear. If you used a normal top, and left off all of the bracing, you'd get a useful reduction in mass. How long would it hold up under string tension? OTOH, a 'sandwich' top can weigh 40% less than a 'normal' one, and have the same overall stiffness. That's why so many people pursuing 'loud' guitars are going to lattice and sandwich tops, to reduce the mass of the plate.
The bottom line is that however you try to optimize brace profiles, it won't make a lot of difference in the weight. I would think offhand that by careful design you could reduce the mass of the bracing by, say, 5%. That's 5% of the (upper limit) total brace weight of about 30% of the top, so 1.5 grams? You can do better by reducing the mass of the bridge, which typically can weigh almost as much as all of the top bracing together.