I did end up buying the shell for 8.88/gal and the supertech was only a little cheaper. Usually the name brand oils are way higher, but I looks like shell wants to sell some oil. I was a little concerned about the CJ-4 rating rather than the CI-4. But I guess people just like to make stuff up about the CJ being bad.
This cummins does not burn any oil in the exhaust but it sure leaks quite a bit out the valve covers, oil pan gasket, and road draft tube. I may need to look into getting some new gaskets. I just bought it and the oil filter was quite old looking but the oil looked real very clean, so either it leaks enough that the makup oil dillutes it, or the engine really burns clean.