Shorter OCI, and lo and behold, no more wear metals!
Okay based on my latest UOA and on tranceformer's, I feel pretty confident in concluding that the German Castrol works well only up to about 4K and then after that it doesn't do a very good job on protecting the bearings (also compare lead wear with my first one) -- no idea why.
The TBN drops considerably after another ~1.5K too, which may be related
Also interesting that the oil was more viscous on the ~1.5K higher OCI -- anyone have any insights on that?
Anyway, this was my last on one the Castrol for now -- next one (at 4Kish) will be Redline 5w30, so we'll see how that compares. If no better, I'll probably go back to the Castrol.
Haven't confirmed this yet, but the Castrol seemed to run a bit cooler, and is definitely cheaper, so if it protects just as well as Redline at 4K, that will be the winner.