What kind of tea you make depends on how you process the leaves or what part you use. Assamica just has larger leaves.
I would highly recommend Camellia Forest Nursery. Last year I bought a few varieties of Camellia sinensis seeds from them and all but one variety gave me a 100% germination rate. It was a surprise for me as I am quite new at this. And people there are great, they helped me with my dying Sochi tea camellia (which I did not buy from them.) They do sell plants also.