Here is what I was able to find out.
http://www.henriquecazes.com.br/imagens/cavaco2.jpgMeasurements used for the classic cavaquinho Medidas usadas no cavaco clássico:
7,5 cm de altura no pé do braço - 7.5 cm body depth at neck
8,0 cm no tróculo traseiro - 8 cm. body depth at butt end
escala 34 cm - scale 34cm
largura na pestana 2,7 cm - nut width 2.7 cm.
largura da escala no 12º traste 3,8 - fretboard width at 12th fret 3.8cm
raio da boca 3,0 cm - soundhole diameter 3 cm.
3 leques apenas, no tampo e duas travessas - 3 fan braces and two transverse braces
3 travessas no fundo com distâncias proporcionais às do fundo do violão - 3 back braces spaced proportionately to the guitar back
There is a luthier in Salvador, Bahia that is using an X brace for his cavacos.
http://www.jpcharlesluthier.com/por5.htmI hope this info helps.