As is usually the case, simply saying you are moving to formal recruitment is not as easy to define as one would hope. I can offer you a snapshot of a chapter I advise that sounds pretty similar to your school.
We have 3 NPC sororities, and formal fall recruitment. Panhellenic holds info sessions and PR tables throughout the summer, at orientation, and around campus until recruitment begins (about 4 weeks after classes start). Recruitment actually lasts about a week and a half. To balance class schedules, only one sorority has an event on a day. The first two rounds are "split parties," meaning the chapter has a 30 minute party during lunch, and then a thirty minute party in the evening. So, ABC has their first round split party on Tuesday, then DEF has their's on Wed, and XYZ on Thurs. Round two splits begin on Monday the following week with ABC on Mon, DEF on Tues, and XYX on Wed. Each sorority has a one hour party that Friday evening. Preference is an hour on Sunday, and Bid Day is on Monday.
To be eligible to be invited to Preference events (and thus, to receive a bid), a PNM must attend at least 1 party of each group- this could be a minimum of one of the 30 minute parties. However, generally most PNMs attend more. Preference is the only round that sororities make cuts, and thus the only round that a woman may not be invited to the party. (Additionally, the PNMs don't have to attend all Preference events to which they are invited, although we've never had an invited woman not come, since all the parties are back to back.)
We don't have Rho Chis or Recruitment groups. Recruitment is too small to need it- about 30 women began formal recruitment last year. The Panhellenic President and Director of Recruitment disaffiliate and act as recruitment counselors for all PNMs.
Now- do I like the process? Pieces of it, yes, pieces of it, no. I think a week and a half is too long, but the collegians seem to like it. Also, lots of Panhellenic drama gets raised because of waiting so long into the semester. But, the campus has found a system that works- pretty well- for them, so I roll with it!

Oh, and no one has been at total for years (don't get me started!) so all three chapters CR year-round, as well.
Sorry this was so long!!!!!!