SoCal the name 'mediovariegata' is an incorrect name, like given to the plant by a nursery. I think your plant is 'Undulata'. If the white in the middle of the leaf is less than 1/3 of the leaf, then it is 'Undulata Univittata'. See this discussion on hostas in the Undulata family.
https://www.delvalhosta.org/un...
But your hostas do amazingly well for your location. Good luck with them.
Here in Ottawa, they should not be showing yet. Or maybe I should be able to find emerging pips by kneeling and feeling. BUT, many of mine are an inch or more above ground and some are beginning to unfurl which worries me because we are certain to get more cold weather. I haven't taken pictures, but from the window I can see a 10 yr-old seedling that's up a good 1 1/2". My Korean Snow is the same. A small border of 'Cracker Crumbs' is up, my 'Wheee!' is also up more than an inch. I haven't gone over the garden with a check-list yet and I try not to walk in it until I know exactly where the hostas are and I have so many crocuses that many of the hostas are lost in a sea of crocus foliage.
I also have a 'White Feather'. I wouldn't have bought it, but a friend gave it to me a few years ago. I need to either pot it or build sun protection for it until the tree above leafs out. What have people done for sun protection for individual plants?