Nothing wrong with being stealthy but the key is not to cast or float your fly line over your target. The fly line color is more to assist the fly fisher instead of hiding the fly line. There are floating lines with clear tippets that you might take a look at.
If you want to camouflage your fly line take a tan or beige color line and get a brown and green marker pens. You can camouflage the heck out of your line. The shadow of the line is more of a problem than the color. A blue line will look good with a blue sky background but what about in a tree lined river or stream. The Blue line will show well against some backgrounds.
If it was me I would not be as concerned with the line color as I would be how and where I am casting and drifting. Making a fly line blend well with the water also makes it much harder for the fisher to see the line to control their mends.
Your tippet is mostly determined by the size and type of fly you are using. Here is a chart
that will help you select the correct tippet size for the size of fly you are fishing.