I'm at 4500 miles on this OCI in my civic. For the next change I'm wanting to try a 0w-20 such as Mobil 1. But I also have 1 qt of Pennzoil Ultra, 1 qt of Mobil Super 5000, & 1 qt of Mobil 1 (all 5w-20) left over from previous changes. Sump capacity is about 4 quarts. Can I make a good blend out of what I have or should I go ahead and get a 0w-20?