I have to ask, what is all this concern about opaque? Years ago guys wore moleskin tights, usually a wool fabric that was meant to stretch, but not much. Can you imagine the joy of a male dancer when he first found nylon?!! The flexibility had to increase exponentially over older fabrics.
So at what price? Sure, early nylons were, or could be, non-opaque, especially when stretched on the body. Some dancewear makers made these in heavier nylon. I remember my first pair of black, male nylon tights from Freed of London, in the 1970's. They advised to buy a larger size. Without being completely stretched, tight on the legs, they were very opaque, almost like long-johns (and would easily become baggy at the knees).
If you think your nylon Capezios are too see-thru, buy a larger size.
And then I also have to ask what's so wrong with some see-thru? I have seen dance performances filmed in the 1950's and the guys' tights often let the pale flesh shine through, but, for the advance in the flexibility, I'm sure the male dancers were willing to put up with the exposure.
balletboy[/i]