Agreed. Most ocellaris and percs do the whole "one big fish, one small fish" thing, and work out pretty well.You should be able to get a pair out of them. If you're not 100% positive, consider buying the one large fish, then the 2 smaller fish (with the intent to sell one of the smaller ones) if it's cheaper than buying a pair online (which are probably for sale due to them no longer being of breeding age). This way, you can assuredly get a pair (either the large with one of the smalls, or both of the smalls).
Sexual maturity for clownfish is dependable upon heat and nutrition (80 F and lots of high quality frozen/live food = quicker sexual maturity), but it still takes quite a while post-hatch, I think it's like 6-9 months approximately? Lots of shrimp and a little bit of squid (no more than 15% of the diet for squid), is very, very nice for the fish.
Also, consider Wittenrich's "Complete Illustrated Guide to Breeding saltwater fish", it's not as thorough as Wilkerson I think (haven't read Wilkerson's yet), but it's pretty good as a beginner's guide to breeding.