You have been waiting a long time for a response. I have successfully crossed Haworthia species twice and two varieties of H. cooperi once. I use a size 00000 (that's right, five zeroes) camel's hair artist's brush to carry out cross-pollination. One should get pollen from older flowers and deliver that pollen into just-opened flowers since just-opened flowers will not release pollen, apparently as insurance against self-pollination. A successful cross will cause the flower ovary to expand, so keep an eye out. When ripe, the ovary dehisces, so you need to collect it before it can disperse seeds. Sow seeds at or just below the surface of your potting medium. Allow the potting mix to dry a bit between waterings once sprouts have appeared. After your seedlings are a few weeks old, allow the mix to dry for a few days between waterings to encourage root development. Do not allow things to stay dry for a long period as you may lose some seedlings. At the same time constant wetness in the potting mix will encourage rotting. Good luck. My first successful hybridization, H. turgida x H. emelyae, carried out in 1997, is beautiful. One of my four hybrid plants rotted 18 months ago, and I took four leaf cuttings (a bit shorter in length than I like, but necessary to avoid diseased tissue). I had one leaf succeed, and it has generated three new plants.