I applaud your ambition. As for picking the clowns, do so with care. Alot of the Hybrids are crossbred to produce those morphs, and as a result hatches can be small, survival rate will be average, but the number of survivers that have morphs making them worth selling will be abysmally small. A pair of black and whites would be a good start, i've also heard false perc, maroon or clarkii are easy to handle. Key is to get healthy stock. I have a friend that did clown breeding for years, He bought 8 of each clown he wanted to breed. He let those 8 loose into a 120g bare bottom tank with multiple clay pots for a month till they paired off on their own. When places sell mated pairs, its sorta deceptive. Mated pairs IMHO should already be laying, not come in a box with the larger of the 2 barely over 3/4". The benifit to buying "mated pairs" is they are pretty much guaranteed to come from different parents. My friend put each pair in its own 20g tank, blacked out on 3 sides. He raised black/white, false percs and Clarkii's. he had 24 pairs going in seperate tanks, all bought as mated pairs, some from different vendors. It took him 3 years to get even half the pairs laying eggs.
If you're doing this for fun, dont spend a large fortune on the setup or the clowns, since it can and often does take over a year for a 1/2" juvy to sexually mature, and can take another year to or more to persuade them to lay eggs. If you are doing it for trade, Great. My hats off to ya. If you're doing this to setup a small time profitable business, dont bother. The market is saturated, which is why my friend who ended up with 14 pairs laying regularly, sold the fish, tanks and everything. he had more fry than he could care for, and more juviniles than he could sell/give away.