I'm not sure I agree with Ken on this.
Certainly the bridge on a violin rock sideways, driven that way by the bow pulling the string across the box rather than perpendicular to the top. That's why the sound post and bass bar combo was such a major innovation. Both had been used separately prior to about 1550, as supports for the top under the down pressure of the bridge, but neither was acoustically much help without the other. The post under the treble foot of the bridge 'nails' it in place, so that the rocking of the bridge acts as a bell crank, pushing the bass bar vertically to drive the type of top motion that produces sound. The active part of the top is narrow, and it it stiff and hard to drive compared with a guitar top, but when you have the continuous power of the bow instead of an intermittent pluck, it works fine. Making it too efficient risks 'wolf' notes; witness the 'cello.
I use the Chladni method of 'tuning' the top and back of arch tops, as well as violins. The procedure I follow is to 'tune' the 'free' (off the guitar) top and back so that they vibrate in similar ways at similar frequencies before cutting the holes and installing the braces. Cutting the holes typically throws everything out f line on the top, but putting in the brace(s) and trimming them properly gets it all back. This holds quite well for both fiddles and guitars. The brace(s) pretty much make up for the stiffness and mass lost to the holes.
I've made both round hole and F hole arch top guitars. There are differences. of course. On round hole ones the 'X' braces (I have not yet made one with 'parallel' braces; it's coming...) don't need to be as big, but you do need a cross patch above the hole. I usually make that low and wide; a 'patch' rather than a 'brace'. On a round hole with parallel braces I think I'd use two patches, above and below.
Gore suggests in his book that we don't really want the sides to be pushed into motion be the top anyway. He adds significant mass to the sides below the waist to 'keep the sound in the top' , which is, after all, the most effective sound producer. The top and back are coupled by air pressure changes in the box anyway, and those pretty much act out of phase with any energy being transmitted by the sides. O'm not as sure as he seems to be that this is a bad thing. It certainly can cut down on the power output of the instrument, at least at some frequencies, but may also add to the 'tone color', which is not a bad thing.
Round hole arch tops do sound more like round hole flat tops than F-hole arch tops do, of course. Most modern arch tops have pretty big holes, for one thing, and that shifts the the 'main air' mode pitch 'way up. Most flat tops tend to have that pitch around G on the low E, with the usual range being from F# (~92 Hz) to around G# (~104 Hz) or a bit higher. Round hole arch tops also tend to come in near that range, or a little higher. Arch tops often have their 'main air' pitch as high as A# (~116 Hz) and as high as C or C# (up to about 135 Hz). This probably accounts for most of the difference is the basic timbre, IMO.
'F' holes can also 'listen' to interior air resonances that the hole in the center can't, and that has to make a difference, although it's harder to pin down in some ways. By the same token, a round hole on the center line centered above the narrow part of the waist can also interact in interesting ways that can color the sound, which are out of reach of holes in other locations.
All of which is to say that there are reasons why these traditions persist, and that are not always obvious. There are, of course, lots of ways to make good guitars, but if you're trying to make something that sounds like, say, a 1920's Loar L-5, then the easiest way to do it is to start by copying the main features of the original. I can't argue with Ken's results; he makes a fine guitar (and gets a lot more for them than I do *) but I'm not sure I agree with his reasoning.
Which brings up what's been called 'the American question':"If you're so darn smart, why aren't you rich?" There is, of course, no simple answer to this.