OIL OIL LAB TESTING What does it all mean??

I just talked to Redline on the phone. Quite friendly fellow.

0w30, 5w30, 10w30, 5w40 (I was told) all have 1373 PPM Phosphorous and 1225 PPM Zinc. In my opinion, selecting the the correct viscosity at 100C of one of those options will cover any bearing clearances of most any motor. Edit: this content number is regarding their pure synthetic. Also, the general specs of their oil can be found on their website: http://www.redlineoil.com/techinfo.aspx

I am probably just switching to Redline for my flat tappet cars and leaving the zddp questions and experimentation behind.

Also, for late model vehicles their recommended drain interval is 10K - 18k for "vehicles out of warranty". I imagine this would mainly be dependent on the pollution of the oil from combustion and waste contaminants on the duration of OCI.