Ok, so be prepared, this is going to be long, and probably sound funny coming from the "new" chapter. We have been around as an organization with similar ideals and rules to Sigma Alpha for 13 years before we became a SID, so we have been through both of the problems you talked about, as well as probably just about any other one you can come up with.
We have, however, managed to repair a similar problem with our AGR chapter. It helps that a lot of our girls know the guys on a more personal basis, through class, ffa, 4-H, breed assoc, etc. Once you get a few friendships, its easy to expand those. We include the guys in our rush events with a social every rush week. This years is "surfer and beach babes" themed. We are having this one at their house, although we have hosted it at a sisters house or on campus facility before. We also attend their functions as a show of support. We have also had bbqs, picnics on a lake our univ. owns, volleyball, we always go cheer on each others teams in intramurals.
Every little thing you do, however small makes an impression. Even if its a Christmas card sent to their house, a thank you note for their attendance, going to their chapter to announce an upcoming activity(sched. prior with their NR), cookies delivered on a late night during finals week, or even stopping a guy in an AGR shirt and introducing yourselves.
As far as the alcohol thing, if the guys respect you as a sister, as a group, and as a chapter who is trying to further your sisters towards the same goal as their guys, then they should respect that we are dry.
As far as rush, for some reason its never really been a problem for us as far as getting enough girls. We had over 80 girls attend information sessions last semester for the Alpha class, and we had 22 MCs, 19 were activated. We just started rush last night for this semester, and we had 29 at our first night of rush. We have set a limit of 30 MCs for this semester, as we have 30 actives and dont really want to get ahead of ourselves. We send out a letter to every eligible woman in the college of ag at the beginning of the semester, before panhellenic rush takes place. We post fliers, update our website, send a mass email to the college, any listservs we are on, maake announcements in our classes. Word of mouth is still the best mode of communication though. Thats where the majority of our girls come in. Dont forget about people out of the college who would be interested, but arent ag majors. Hit up the FFA chapters and 4-H chapters in your state with fliers.
Also remember though, that you are looking for quality women who will be dedicated and actiive actives. When you get to be as large as we are, you get into a whole other set of problems that require a different approach. As long as you stay above the minimums, then you should be proud of the girls you bring in, however big the class might be
Tiffany