2) The company that I'm thinking of going with has quoted removing the existing old paving and about 12 inches of gravel underneath. I have warned him about my underground power line to the garage. He says he won't hit it. He has quoted 4 inches of 0 - 3/4 stone as a base, compacted. He didn't say anything about wetting it, and I agree with you that wetting it sounds like a good idea. I don't know if he is using limestone, I notice that in your photos, your base is a light yellow colour, here they use stone that is gray, like gravel.