Hi A..
Here is a web site that may help. I suggest checking out the whole site but here is an interesting page.
http://www.in-gender.com/Gender-Selection/Oplus12/
For more details on the Shettles Method there is the following book,
How to Choose the Sex of Your Baby: The Method Best Supported by Scientific Evidence
by Landrum B. Shettles, David M. Rorvik, David M. Rorvik
You also may benefit from getting a fertility lens.
The Lens can tell you when you are ovulating and it is great for any woman who wants to know when she is fertile so that she can conceive more easily. )or avoid concieving.
Fertile Focus
Personal Ovualtion Microscope
Reusable Unlimited Tests
Natural Safe SAliva Based Testing
Accurate and Easy to use
98% Accurate
100% safe
This product is described well and is available for purchased online at http://www.fertile-focus.com/
or I have seen similar products at HEB. I don't know the quality of the other products-magnification, light source ect.
I am a Birth and Postpartum Doula and I own The Mothering Way, a group doula practice in Austin TX.
I hope that helped and I am sorry that I do not know which method is best for concieving a girl but this is the research that I know about.
Take care,
R. George,CD(DONA),PCD(DONA)