I also just had a m/c. I do however have a wonderful 18 month little boy. For both my pregnancies I did not test positive for 4 days after my missed period and have wasted about 6 hpt as well. I even went to the Dr and got a neg. result with my son. Some women don't have enough HGC in their urine for a while. I would take her in for a blood test if she doesn't start in a week and is starting to get some symptoms. Good luck!!!!!
I know that with my first daughter I was like close to 2 weeks late before a positive showed up (and that was a blood test) I did 3 urine tests AT the doctors and all came up negative.
You guys sound like my husband and I ... I was addicted to peeing on sticks while trying to conceive. It sounds to me like you guys are doing an excellent job of tracking your wife's body to determine her normal length and therefore determine when she likely ovulates to increase your odds of conception. I would say that you are right on track. Don't forget that it can take a normal, healthy couple under the age of 35 one year to conceive, so don't be stressed out if it takes a while. I would get so frustrated each month that I was negative, but that positive day will come (it just takes a bit longer for some of us than others).
The hardest part is not getting your hopes up each month. Try your hardest to refrain from getting too excited because your wife's emotions can actually cause her period to be delayed and can actually induce false pregnancy symptoms. I know that I tricked myself into thinking I was pregnant numerous times and it caused my cycle to be off that month. However, once I discovered that my average cycle was 30-31 days, I was able to decipher that I ovulated around cycle day 16 or 17.
You are right on target to try testing with numerous brands. I would recommend using first morning urine or having her hold her urine for at least six hours and refraining from drinking water during this time (because this can dilute the hcg in the urine) ... this increases the likelihood of picking up the hcg in the urine if indeed she is pregnant. Just remember that some women don't test positive until a week or so after their missed period. I was one of the lucky ones who tested positive at 11 days after ovulation. I also highly recommend using OPK ... the first month I used an ovulation prediction kit, I discovered that I was actually ovulating later than I thought, and I conceived that same months (after 15 months of unsuccessfully trying to conceive).
I wish you guys the best, and I truly hope that this is your month. Best wishes to both of you!