I just weighed them...
My scale only goes to the gram level, but here are the results:
Carbon fiber toggle - 1 gram
Aluminum toggle - 2 grams
I just ordered a set of aluminum toggles to replace the CF ones...I guess I'll be carrying a couple extra grams with me next trip.
My toggles have short loops of string on them and I tie them to one end of my tree strap so they're always where I need them. About the only way I could lose one would be if the string broke or if I lost (or forgot to take down) my strap.