Best to grow all the pale variegated leaf forms in pure pumice.

Nice looking sans there. :)
Apparently pumice is not easy to find in many parts of the USA. Would potting it in pure perlite be the same kind of effect?

Perlite works except for the fact that it floats and can wash out when watering. Is there any volcanic cinders available or even sand for potting?
Avoid peat moss as this can be harmful when the media breaks down and increases acidity in the mix.
If you are using a potting mix, use a fine bark mixed with perlite for best drainage, then add some river sand to break it up.

Hi summersunshine,
You don't say where you live, or if you have to bring plants inside your house in the winter, but I live in east Tennessee, zone 6, and I bring many Hahnii's through the winter, inside my house, with no watering. So I agree with Smoley's suggestion.
Also, I disagree with the suggestion to avoid peat moss. I hear this a lot with Californians. I use peat moss (and perlite) exclusively and have always had excellent results.

I live in zone 5 so it will be indoors in the winter.
Thanks to both of you for the advice!