OPK Advice Please!

This month I decided to use 2 opk because this is our last month of trying naturally before IVF  and yesterday I got the blinking smile from Clear Blue and today was the solid smile. Both days with FR the control line is significantly darker then the test line. Which is more accurate? I do chart my BBT and don't see an increase yet so I know it's not too late and I BD first thing this morning. Any advice out there?