I agree with Roland.
Easy to keep small polyped scleractinians include Hydnophora, Montipora, Anacropora (if you come across some, please email me where you got it from-
Leathercoral85ga@aol.com), Pavana, and Seriatopora.
I would first start off with some captive raised Hydnophora, then move on to Montipora and then Pavana. If those are thriving (not just surviving, but they're showing good polyp extention, growth and coloration), then you may want to try Seriatopora hystrix and possibly Anacropora. Once you've good success with those, then you may want to move into the Acroporids. As Roland said, the A. yongei would be a great choice. They're fast growers and have great electric green coloration. Pocillopora may also be a good choice.
Graham