Hello Mike,
Like Nick, I wasn't too keen on yarn indicators, until I found and used these:
http://globalflyfisher.com/fishbetter/indicators/
Simple to make, very visible, lots of color combinations (two colors of yarn make them easier to see in different water conditions) and float extremely well. I like to brush some Frog's Fanny floatant into them for extra bouyancy.
Cheers,
Richard in Plano, TX