I agree with w8ye. Use the same oil and ratio for the life of the engine. Synthetic oil is slicker than dino-oil. The argument has been to use the dino oil for break-in as it would allow the ring to seat faster than synthetic oil. The early DLE engines were known to come with a very hard ring and therefore a dino type oil was preferred. However, I think the rings DLE uses now are somewhat different from the originals and so you may just choose the oil of your preference and stay with it. I don't think using different oils are really necessary.

Mike