Mike,
DO NOT GO DOWN THIS ROAD!!!
Like Paula said you are putting undo pressure on yourselves.
True story
My older brother Ken and his wife Kim did exactly what you guys are doing timing and all kinds of crazy stuff for years and she never got pregnant they got so upset they adopted two boys (which was great they are both beautiful boys) they are both married now and have contributed to my moms and dads 35 grandchildren and 6 great grand children (I have 9 brothers and sisters). Once the pressure was off Kim had 7 kids of her own. It seemed every time her looked at her she got pregnant.
Make a game out of it Linda and I really did these things.
We got a jar and every time we had sex we both put a quarter in she got pregnant in about two months, but we had enough money in the jar to buy dinner to celebrate.
We had sex in every unconventential place we could find then when she got pregnant we tried to figure out where we were when it happened.
Brenden was conceived on top of MT. Southington Ski area it was a beautiful fall day for a hike.
Brett was conceived in the back of a Chevy Impala by the res. in Lexington, MA. I remember the windows were all steamed up.
Make a game of it and nature will take its course. Have you ever seen one of those reproductive shows on the Discovery channel those little buggers are resilient as ****** and I heard once that if compared to the top runners in the Boston marathon where it takes them 2 + hours to run 26 miles it would take them twenty minutes.
Have fun !!!!