That would depend on how you were pronouncing them.
Is
Helene- He-layne or Hel-eene?
Is
Helena-
Helen- a, He-layne-a or Hel-ee-na?
I wouldn't use either, because I have had to live with a name with two legitimate pronounciations, and I can tell you it does get a bit tiring.But I would say either
Helene prn. He-layne or
Helena prn. Helen-a.
Probably
Helena is my favourite.