I don't have either of the two you mentioned or know when seeds should be sown, but there is a thread somewhere in here with a long list of appropriate vines. I have a lilac vine (Hardenbergia violacea) and a snail vine (Vigna caracalla); both do exceptionally well in the sun and heat on the east side of the house. I also have a coral vine (Antigonon leptopus) and also a pure white bower vine that is in the same family as the crossvine (Pandorea jasminoides) on west-facing walls, which also do quite well.

Here is a link that might be useful: Colorful Vines for the Hot Desert thread