Actually, the trick is to find the right combination of scale length and string mass.
Yes, a longer neck scale length would help, but if you put thinner strings on it, you'd defeat the purpose and be right back where you are.
Because tuned to a given pitch, the string-mass/scale-length/string-tension relationship is like a three-legged stool.
The clunky tone comes from a string's being too loose in relation to its mass and scale length. So to eliminate it, you have to increase one or more of the three elements. Increasing the tension without changing string thickness or neck length simply means tuning it to a higher pitch; increasing the neck length without changing the tuning or string gauge results in greater string tension (and less clunkiness); increasing the string guage without changing the scale length (while tuning to the same pitch) would also mean increased string tension (and less clunkiness).
Of course, there's a point at which one of the elements becomes out of proportion to the others, and then it just sounds dead. Most standard 8-string sets come with an 0.74 on the bottom. If that's too clunky, an .080 or an 0.85 might sound better, but a .100 might be too thick to vibrate much at that scale length (hence the deadness)...
You are right - It's quite a large task to get it right, and there are so many companies and traditions that are not reaching the ideal, e.g. I got a nice solid-top tenor acoustic (standard scale length), standard set had CGDA = 32, 22, 14, 10
I never ever break strings, and with this guitar, it took 3 strings to get a top A string fitted without it breaking. Looking at the tension chart
D'Addario Strings : Other Instruments : D'Addario J66 Tenor Guitar Strings,
You can see the top 2 are way tighter than the bottom 2.
Anyway, once past that, I found the instrument sounded very shrill and unbalanced, a very percussive, metallic honk from those top 2, and they felt wrong - too tight compared to the bottom 2.
I fitted 32, 22, 13,9, and it was better, and when I took it to my luthier, who had supplied it from the distributor, he recommended we tuned it down 2 semitones to A#, F, C, G. Now it sounds lovely - properly woody, the top is driven well and the guitar is so expressive. So why do people fit the tight CGDA set? Only advantage I can think if that it would have a louder mandolin-type tone when strummed with a pick unamplified in a folky session.
As I state in my other post - the baritones I have defy many people's expectations - there is a lot of confusion out there. I do have a 30 inch Aria/Esteve classical, an octave down (Contrabass string set). It sounds wrong to me, and I have a "Quintbass" set of strings ready to try.
My standard advice is - dropping the tuning too far destroys the tone and feel of the guitar (both electric and acoustic), and most baritone guitars do go too far. With standard setups, most 8 strings are closer.
I think - don't fit a 16-70 set on a normal length 6 string, or a 27 inch. It does work on 29 inches
for a 27 inch 6 strings, go up 1-2 string gauges, drop 2-3 semitones, or else it gets un-guitar-like
For an 8 string, those bottom 2 strings neatly isolate the problem, 27-28 inch is probably the right length - longer would spoil the top strings I think, unless you go fanfretting. I haven't tried a fanfret electric. I tried a Taylor one which was easier to play than I thought