With my first miscarriage, 8 weeks measuring 5-6, I ovulated on CD 16 (counting the first day of bleeding as CD1), and that was only a day or 2 later than in a normal cycle.
My second miscarriage, 12 weeks measuring 9, although I bled for a week longer, I still ovulated on CD17.
Both my miscarriages were totally natural so i don't know if that affected my recovery or not. I know there's a high rate of variance from woman to woman.
I never used OPKs but I did chart and yes they were basically normal cycles.