[Firehouse]

I'll tell you how the guys do it, and you and I agree that guys and gals are different. However, I was personally involved in helping a sorority return to campus using "male" rush techniques (outside the formal rush structure), and it was, and is today, a fabulous success. Very proud of them.
With guys, the core group decides on a template of sorts: ie. the look, the personality, the character, the ability to pay dues, etc. All new guys have to fall somewhere within that outline. That ensures that the fast-growing chapter maintains a distinctive and compatible personality.
The chapter provides backdrop for the rush effort. The core rush group seeks out the right targets, solicits them and puts them in the company of the chapter. One by one they are bid, and pledged. In my undergraduate fraternity chapter today, the rush committee meets every night after rush open house. It is their job to select the targets, and to plan how they will be pledged. This group of perhaps 15 men choose the pledges on behalf of a 175 man chapter. As a result, the chapter has a very compatible membership and every pledge class is on the same quality level as previous classes. The chapter's stated goal is to "win rush".
In a small fraternity, the best results with a paid rush chairman come when he surrounds himself with a core group of true believers who want to raise BOTH the numbers and the perceived quality of the membership. In those chapters there will be a period of time where each successive pledge class looks better than the one before. That's why it's so important (as others have pointed out) to have excellent pledge education and fast initiation. All pledging decisions are made by the rush chairman and his committee.
We did this with a sorority returning to campus after a year's absence. None of the former members were allowed to return as undergrads. National sent in a hired gun and she surrounded herself with young women who fit within a certain template. And yes, looks were a part of that. One problem the old chapter had was that they couldn't attract new members who didn't have the same problems the old members had. It was a fabulous success. As I recall, they didn't compete in formal rush the first year; they just continued to build and build their membership. Today, they are constant at around 150+, and are very popular and happy and stable.
The short answer is: the hired gun and her crew choose the candidates. Period. Panhellenic may have rush rules that would prohibit that during formal rush, but it solves so many problems during open rush. You have no long emotional meetings, no energies spent keeping the chapter from making bad decisions. All energies focus on rush. We say, "Everything about the fraternity is fun, except rush. Rush is business."