I cannot deal with designing here. For this I recommend my book with the title
"The Classical Pocket Watch Case" (in English available).
From acyl glass plates in different thickness one turns rings on the lathe, for the case band, the front bezel and the back bezel of the outer sides, also rings for the inner bezels. These rings, except that of the case band, take up crystal glasses. These glasses form the front and back cover, another one is intended for the Savonette glass.
Acryl glass is very sensitive, as already said. So it is to be noted that with slow revolution is to turn. The burins must be polished to a high standard. Afterwards by means of the slide rest parts are turned, they are to after-turn with polished burins by hand.
Thus one reaches already approximately a polished, transparent surface.