What BBT thermometer do you use? What I mean is does it give you results: A) 87.8 or B) 87.87 I use a thermometer from CVS thats considered a basal one. It gives my my temperature in (B) format (87.87) But which is better? ----Edit----- What time of the day do you test with an OPK? Do you not drink or pee hours before doing an OPk?