
Your best guide to the right days to mate your bitch is a good stud dog and the bitch herself. You only need to see that inevitabley when a bitch is mismated by her or a males own desire they seem to become pregnant.
If you mate on alternate days up to the point she will no longer stand you will have found the right days, after that it is a matter of whether she ovulated, and the fertilised ova implant about 3 weeks later, and then whether hormone levels maintain pregnancy and developing fetuses are viable enough to reach term.
If you cannot allow about a week to 10 days for the bitch and dog to be tried together then your only sure way to accurately predict ovulation is progesterone blood testing. If there was something reliable simpler then it would be used by reproduction specialists.
As the conception rate in bitches served at roughly the right time is very high anyway this would account for the supposed success of any other purported methods, including the owner wearing green at time of mating,
Yes I am a sceptic. Good luck.