I'd recomend a roll off of arround 95hz. I used to do it a little higher then that and wasnt happy with the weaker bass.
As for stealthing. I'd recomend getting a pair of glasses if you dont wear them to start with. Even without prescriptions. This way you can have something to put your mics on for stereo seperation. Also, this gives you a reason for the visible mic cords. Also, pick up a lanyard type thingy for glasses, and place little hooks at the middle (or bottom where it will hang in your neck), and at the tops. This allows you to conceal the wires from people sitting arround you (who *will* report you sometimes... man that sucks hardcore, stupid "citizens arrest" type people). Also, this helps if you get stuck sitting next to security (I have), you can still get away with it. Last, buy a nylon windbreaker which is a similar color to your mics/cords and thats how you can get them in. Clip them to the neck of the jacket, and roll it outwards, like you weren't careful putting it on, and minus metal detectors, i've never been caught. I've never had to deal with metal detectors, but at the same time, i've never been caught either. ^_- There are some other things, but thats a good start.
If you'd like examples of all of this, let me know and I'll take pictures and post them. I once wrote a guide on how to do stealth taping as I've done a *lot* in situations where it was extremely hard to get in and stay hidden, such as crowds of 40 or less where there were 3 or more security people... (or what I call "critical" situations as it is critical that you be careful in order to not be caught, not so much that the tape your making is critical).