I've got a pair of clowns, one probably being about an inch and the other a bit over an inch and a half.

There's a lot of threads on this topic, but answers are usually something vague like "not too much" or "once every day or every other day."

I'm feeding them Formula One small pellets right now. I usually put in about 5-8 pieces, and they disappear the second they hit the tank. After that, they eat up a good amount of the phytoplankton that I put in. These fish are great eaters.

Specifically, around how many pellets should I be feeding them at a time? Can the fish eat themselves to death, or is the worry about overfeeding only about having too much waste? My cuc gets anything that hits the ground.

Your doing fine, some people feed more then one time in a day its really up to you. Also most people when they are talking about overfeeding there thinking about what kind of bioload the overfeeding is creating not that there fish are getting too much. I personally feed my tank twice a day and it seems to work out.