You can take Agnus Castus at any time but only up to O. I'll stop taking it, and EPO, when I get either a positive OPK or a big temp rise. I take vit B6 because I found out last cycle that my LP was only 10 days so I would like to try and lengthen it a bit. You can take B6 all the way through your cycle - I take 50mg per day, as well as a vit B complex.
I find Pregnacare Conception reassuringly expensive - I figure it must be doing some good if it costs that much lol And I get mine from Amazon, so it's only about £6.
I would maybe take a more relaxed approach and not be taking so much if I was a bit younger and had a bit more time. But I'll be 34 this year, so I'm throwing everything I can at it!!