I don't do 10-gallon batches, but I use a Koelsch/California Ale yeast blend for my Apfelwein fermentations. I don't have the equipment to see how they are behaving, i.e. whether one strain has become dominant, but the results are very enjoyable. I just keep reusing the same yeast cake. I am sure it'll eventually need washing, but thus far I haven't had any problems with autolysis or other yeast breakdown-related off-flavors.