In my experience, hinged swim-baits are not as difficult as they may appear. Yes, they are certainly more involved in the build, with the hinges and multiple sections to ballast. A lot of planning to get all the hardware to fit into the small spaces. But, my success rate is 100% I literally cannot remember ever having a hinged swimmer that I failed to get working. I certainly could not say the same for crank-baits, which has been my main build experience.
The most important thing with hinges, is total freedom of movement. Not even the slightest rub is acceptable. The swimmers that did not work first time, were solved by fixing rubbing hinges.
Length distribution is probably important. The nose section slightly longer than the rest. But a precise formula is not necessary, there seems to be a lot of leeway. I use something like 3:2:2:2 I have read of others using 2:1:1:1. Look through the gallery and web and see what proportions others have used.
Ballast low down for a vertical swim. I like to ballast mine so that all the bait floats horizontal, believing that this relieves rubbing at the hinges. Others think this is not necessary. Many do not ballast the rear section whereas I generally do if possible. My point is that there is no fixed formula, the baits work.
Dave