Hi

Sorry , I didn't ansver this question ;

"2) Are displacement/stability parameters easily calculable by a
formula
or design chart for each scale ratio?"

Easy --- as curves describing the exact displacement for stability.
Waterlines and secions follow useal drawing rules but 3D-H expand
this perception now you can make double hollow structures things you
can't emagine but master on a screen, ---- and it will be there when
the framework is assembled.
For thousands of years naval architecture been in the minds of often
totaly unskilled craftmen producing the most beautifull wonders, in the
17' century in this contry, only the king could build knowleage such as
top technology naval design was for the few, an academic issue about
keeping the secrets to oneself , I build and designed boats none of
these failed but beside I am a boatbuilder lectured boatsbuilding
acturly, proved my idears and abilities as profesional you can be,
being surrounded by famous and known designers and architects --- do I
maneage to design a rugid life saving boat do the sun rise every day.
What calculations do you want --- acturly it's about doing it simpler
avoiding the calculations or make them do somthing , alway's wondered
what people want these calculations for, it's all there when you build
it.