Burning oil

I didn't think about the oil thinning at temp

So two possible explanations:
1. Rings. Possible detonation damaged rings/bore. Explains result of compression test. And suddenness of symptoms.

2. Valve seals/guides. Heads probably have 200,000 miles, possibly original guides. I got them at 180,000 miles and have touched everything but the guides. When engine is cold, oil is too thick to get past seals/guides. After it's warmed up, oil is thin enough to seep past under idle vacuum. Need to have someone follow me while driving and watch the exhaust. What could be a possible "switch" to cause the smoking? Guides would wear slow and slowly open clearances. I've been running Driven GP-1 15w-40 synthetic since rebuild.

Are there any better ways to test the two? Look at the tops of the intake valves? Any more symptoms of the two? Anything I've explained happening that doesn't make sense for one or the other?