I know a couple of guys who manage to get themselves amazingly flat, but I finally saw one guy's "before" pictures (he just had surgery), and he wasn't very big at all.
A lot of factors contribute to the overall look. Size, shape, how dense your tissue is (mine was pretty dense), what kind of binder you have, how you manipulate the appendages underneath the binder. You might even need two binders to get the best effect. Not much fun in the summertime, but it's something to consider. And what Mister says about layering is good advice.
Also, remember not to look DOWN at your chest--look at it head-on in the mirror. The bumps always look more prominent when you look down. Having the unbuttoned shirt as your final layer will also minimize the bumps that remain in profile.
Let us know how it goes, okay?