I've only ever grown one cultivar of helenae, which is obviously a small sample size to draw strong conclusions from. I can't say I know the secret to them. Knock on wood, this helenae seems to be happy with my care so far (and it's been awhile).
If I were to best summarize my growing conditions it would be: Phrags love me, but Paphs and I sometimes have a difference of opinion in terms of what qualifies as acceptable living conditions.
I grow my plant indoors under LED shop lights. I have a tendency of watering too frequently, especially in the cooler months when many Paphs prefer slightly drier conditions. And yet my helenae seems to appreciate my over watering tendencies. Your mileage may definitely vary there. Indoors it doesn't ever receive particularly extreme temperatures either way. Nights rarely drop below the upper 50s F (~15C), and day time highs basically never exceed 85F (29.5C). I've never subjected the plant to anything more extreme than that, so I'm uncertain how tolerant it is of conditions that are significantly cooler or warmer than that range.
Also, there are lots of terrific helenae hybrids that inherit many of the charming characteristics of this species and usually with the added benefit of being more vigorous, easier to grow, and sometimes even capable of blooming multiple times a year. Those might be an option to consider (unless you're a species-only enthusiast, not that there's anything wrong with that ).