irishpipes:
The letters thing is sometimes about the culture of the organization and/or people not wanting to represent their organization as "the group that screams uncontrollably with beers in their hands." I've seen older members wear letters when drinking, because they say it's about how you act and not what you're drinking, and I've seen older members say wearing letters when drinking is inappropriate.
emcr01:
I don't know what the venue will be or what you all will be drinking (wine and mojitos versus beer and shots). I'm answering this partially based on my experiences with the culture of my sorority--I wouldn't do a "saying." I would put the shirt in your sorority's colors with the word "ALUMNAE" on the front and
maybe also spelling out the sorority, which is different than having the letters/symbols. I've seen that done with NPHC and NPC before. I would personally prefer the shirt in the org's colors and just the word "ALUMNAE"---not particularly fun but very...alumnae.