The problem with fishing small nymphs for carp is that sink rates for these flies are often too slow. A slow sink rate can be an advantage with carp, but lately I have found myself in scenarios where the nymph drifted harmlessly above the carp's head because it just didn't sink quickly, causing me to then hazard another cast to get the fly further upstream and allow more sink time before it got to the fish.
This not an issue with a larger carp fly, wherein bead-chain eyes and the weight of a few rubber legs drop the thing like a stone to the muck. The best you can hope for with a small nymph is maybe a few wraps of lead around the shank before you dub and/or a beadhead. And since I don't like using beadheads on my flies, I'm doubly screwed on this front.
Which is why I started thinking about woven nymphs. These flies are dense, heavy, and designed to sink like stones. In other words, exactly what I am looking for. I also like the two-tone color pattern with woven nymphs. You can make the belly of the fly a light color and the back a darker hue as is often seen with natural bugs. Also, these are typically tied with embroidery thread, so available colors are endless.
Here is a link to an excellent video tutorial on tying these cool flies.