The original was not leather. This seems to be a common misconception. (I was fortunate to have an original suit for a few months to study and pattern)
It was basically the same vinylized spandex material you are using, you just need to spray the pieces with a satin clear or the color you want. If you look at stills from the film, you can see in a number of them, a pretty good shine off the suit fabric. The original suits started as silver, and then were painted to get the other colors. The suit I looked at started as silver, then yellow, red, then back to silver.
However, on your suit, the legs are way too tight / form fitting. The original had spiral wire duct hose in the arms and legs, so they formed a straight cylinder.