For the wings I wound about 1.5 yards of the solid colour on one shuttle and about 1.5 yards of the variegated colour on the second shuttle. I hate trying to match up the colour distribution in variegated threads when I'm part way through a project so I tend to use more thread than I think I'll need so that I don't have to play match up. On the other hand I don't like to waste thread. It's a constant battle. "use more!/don't waste it!" I also don't use precise measurements. I generally pull off an arm's length of thread and then add a bit more if I think I need it.
The wings begin at the bottom and when using 2 colours, start the first ring with one colour and hide the ends of the second colour as you tat it. RW and tat the short chain with the second colour and begin the first large ring with the second colour, doing the split part with the first colour. The next ring is also a split ring split on the side. The third large ring is a normal ring done with the second colour. The last large ring begins with the second colour and the first colour is used on the split side.
There's a short chain followed by one inward ring in the second colour and one outward facing ring done in the first colour. When you reach the bottom of the wing again, switch shuttles and tat with the second colour. The next two inward facing rings are done in the first colour and the outward facing ring is done in the second colour, which is also used to finish off the wing.
The second wing is done the same as the first wing, except that if you choose to do front side/back side tatting, you'll need to switch stitch order. Personally, I think life is too short to play around with fs/bs but do it the way you want.
Anyway, here's the pattern. Let me know if there's anything missing on it and just to make it easier to refer to both picture and pattern, I've added in the green and yellow butterfly again.
Edited: Green just didn't do it for me. I just had to tat it in red. So now the butterfly is in red and white.