OPK - almost + vs. BFP

So here's how my LH surge goes around the time of ovulation:  I get a day of almost positive, a day of definite positives, and another day of almost positives again (which I know one could argue is just negative, but the line is still much darker than all of my normal definite negatives, just not quite as dark as the test line).  Do I likely ovulate 12 - 36 hours after the initial surge (when I notice the rise/almost positives) or is it more like 12 - 36 hours after the absolute positive LH surge?  I've read conflicting information about the initial surge vs. a BFP opk and I'm curious to know.