Tight is good. My rule of thumb is to hold the lever out parallel with the axle and tighten the nut on the opposite end till it's finger tight. Then I push the QR lever in so that it's perpendicular to the axle. If I'm not able to push the QR in that much, I back off the nut on the opposite side a skosh.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.