No, there really isn't another first food for clownfish larvae that you could possibly use. Set yourself up a rotifer and phyto culture station. Your clowns will lay eggs about every 2 weeks, this gives you time to be ready for the next hatch.
He is dead on. If your feeding your clowns enough food and a good mix of food your pair will lay eggs all the time. And I have tried several cluthces on dry food, zero luck.
Get some Rotifers, Instant Algae, and some Cyclop-eze. And read read read. Its possible.
Stick with it
T