Sandra - are you saying that yours are supposed to have those curled up leaves? Never seen a hoya like that - looks diseased or mutated if you think it is supposed to be like mine and Pikevi's. I have variegated ones too that are smaller - and yes, they will not get any bigger than the pots you put them into and allow them to grow - I've noticed this as well. Here is my big one today - not the best pic but you get the idea.
I have mine in a standard potting mix - they seem to do well where sunny and warm.
Here is a link to a grower of Hoyas in Hawaii along with lots of really good pics of some of the different varieties. See what you have to look forward to Pikevi!? You will have to post a pic when yours blooms - yes, very sweet and strong!
http://www.bigislandgrowers.com/ghp/AH.php
Enjoy! mike