[Pansy-Mae]

I also read (not here) that Wild Yam should be avoided as it's not 'proper' progesterone, but plenty of people seem to be using it for BE?

I can't help with much of your post I'm afraid, but to clarify the Wild Yam question, at least:
Wild Yam does not contain Progesterone, so from that point of view it cannot contribute to NBE.
It does contain Diosgenin, which in a lab, can be converted to Progesterone via a 3-stage chemical procedure, to produce 'Nature-Identical' Progesterone, however there is no known bio-chemical pathway in the human body to make that conversion naturally.

I believe that there is may be some slight evidence that there is possibly something currently unknown about WY which may have some sort of effect on NBE, but it is unquantified at present.

So, although there is no reason why you should actually avoid it, there is also no good reason to take it either. You'd be better off spending your money on something else.

Hope this helps a little