It is quite common, I'm told, for Irish anglers to take a fly outside and hold it up against the light, before buying it, to see the colours in the dubbing. I will often mix colours even to come up with the same overall colour that I started with. A mixed colour dubbing is always my preference over a single colour. Single colours seem kind of flat by comparison. I suspect that that is the great advantage of the original Tups Dubbing. I doubt tups testicle hair as any magic fish attracting properties.

For flies smaller than 16 you could try split thread dubbing.