On the front I have 4 leafs out of the seven it started with. The two top longest ones, then every other one. On the rear, I have 6 out of the nine. The two top longest plus very other one. This is how the spring shop suggested I do it, and since they have been in the same family since 1920's, I figure they know something about springs.
I run a 250 cubic engine, which is about 20% lighter weight then the older stock engine, so this is why I can get away with only four. Fronts are new springs, the rears are still stock '37.
Joe