Numeric Street Names

I have an address in my current project that involves a numbered street. I've had it as "52nd Street" but just checked the Chicago Manual of Style, which recommends writing out the name as "Fifty-second Street." While I tend to be a stickler for grammar rules, this is a case where I think common usage (and what looks better) deviates from the rules. The written out version just looks awkward.

What does everyone else think? Should I follow the rules or bend them?

It is how it is shown on letters, but general grammatical rules in the U.S. dictate certain changes between how you would address something on an envelop and how you would write it in a sentence. The biggest example is writing St. when addressing something but Street within a textual sentence.

I had always assumed numeric streets were written with, well, numbers even in textual sentences, and today was the first time I had ever seen anything to the contrary. I tend to trust the Chicago Manual of Style, and I will admit that much of this is curiosity on my part. My gut says to ignore the rule and go with general convention, but I'd like to hear the expert AW opinion.