What part of CA? That is my home state,living in MA now.
Regarding laminate construction, sticking to two halves made from the same wood (any hardwood species will be fine) will make your life simpler, but maple and cherry are both suitable and more than robust enough. Depends on how you want your tiller to look.
Be prepared for a long wait with Alchem. I have purchased prods and ticklers from Slo Bows with no problems at all, great customer service and fast. Super nice guy, too. I have no expertise with leaf springs, but others here may be able to advise.