Hi, gals. I'm afraid I can't answer any of the questions about nursing's effects on LH, etc. (I just know about the effect on prolactin itself, though I believe it also can or may affect progesterone, but that's later, right? Arrggh, and we thought PMS was complicated).
Anyway, I'm currently nursing my 28-month old DS and used my first OPKs earlier this month. I got at least one positive, or at least that's how I read it. I'll know next week if it was accurate, and I'll let you know!
Sorry I can't offer much in the meantime -- I'm curious, too!