Work on twisties too, as welll as stringer and murrine. They are loads of fun and you can get some nice effects right away.
Kiln wash on its own won't work but you can find some things easily enough in a local pottery store, or order online. I tried making my own ages ago, but it was easier in the end to buy and use my time for something else. Lots of info online, I think I used a recipe I found here on LE, with search.
Do whatever is quickest now to get you going, and fine tune it later. We all do
