Germination advice on Cypripediums

[krisk]

I was hoping someone might have some experience sowing any of the following species? I'm not looking for media recommendations per se, as we use our own, but I'm looking for things such treatment of seeds for best germination, pH of media, germination in dark vs lights or any other pre-treatments. Trying to keep it fairly factual, as there are many unproven things people do in the pursuit of germination of terrrestrial orchids. I've had germination of some of these before, but only in limited numbers. Cyp acaule for example I believe requires a fair low pH for good germination?

Cypripedium acaule
Cypripedium arietinum
Cypripedium passerinum
Pogonia ophioglossoides