Don't expect them to breed if they are still small - the female usually needs to be about 3/4 of their maximal size to start breeding.
The trick to get them started is to add another pair of fish that spawn easily. I used Pseudochromis fridmani in the past because I wanted to breed them too and because it usually take about 2 weeks for them to get to it if you pair up a nice fat female with a larger male. Calloplesiops altivelis pairs work well too but might be a bit large.
I think the key is to get some sex hormones into the water as a trigger for the clowns to get into the mood.
In the late 90s I had 1 pair ocellaris, 3 pairs of percula and 1 pair of clarkii going. The clarkii produced a nest about every 10 days and I was able to raise around 800 to 1000 per clutch. The ocellaris and percula usually yielded 400 to 600 per clutch every 12 days. The real problem was not to get them to survive the first month but to get them growing to sale size.
Food, water and electricity during the grow out period was costing more than what they could sell for so after a while I had to scale it down because I was running out of space and money.