My current sourdough pizza is 85% white wheat, 15% Spelt. Fresh milled in a mockmill 100. Both sifted through a #40 sifter for ~85% extraction flour. My starter uses white whole wheat, but I feed my levain Spelt for use in the dough. This has produced a crust that my wife approves of and allowed me to replace an all white crust with. I've found that we really like Spelt in both pizza and bread. Give it a shot!