I wouldn't keep peace for to long. Conquer a rebel settlement or two, build up your army,... MAke sure you build your mines as quick as you can. Why you shouldn't wait to long? How longer you wait the more and better units they have. If you struck soon you'll see only a few pezhetairoi and if you verry lucky (or infortunate, depens on you) you'll see a agyraspidai. Go fast and go for seleukeia and Susa. If you got these you got two of their big 4. The others being Antiochea and that settlement in Anatolia where they can get mines. Having these two and the 2 north of these, will have made you strong enough for building up and conquering them. The only city that will produce elites somewhat soon left is Antioch, but they should be dealing with the Ptolemaioi. (Make them your allies, and if you can afford it perhaps give them some cash to keep them Sel. buzzy.)