The only other marginally tricky bit is the tail. I use two different colors, both green and natural grizzly. I've been putting the green inside the grizzy but may switch it up. Green and rootbeer or brown might also be cool based on what you're imitating.
These are nice for using the tips of hackle feathers that are too long to be suited for flatwings. If the tip feathers aren't quite stiff enough, a small hank of bucktail or a stiff synthetic run down the middle of the tube seems to help with hook fouling.