>>>*One point to make here is that thr compression rings control compression, the oil rings control oil.

You can remove the oil rings completely and get a normal compression reading, so external testing such as a compression test or even a leakdown test is at best an indicator.

Oil can get into the cylinder from just three sources. It can pass upwards by the rings, it can come down through the oil seals, or some type of outside introduction.

Since you had coolant getting into the cylinders prior, my best guess might be some stuck oil rings, or they simply failed.

One test we use for this is to have someone rapidly work the throttle, we call it "jazzing" it. This will result in bursts of smoke if the rings are the issue.

The part here that isn't quite right is the heavier smoking at idle and part throttle? This would suggest perhaps some oil seals not properly seated or the wrong size/type. The factory type steel clad with Viton lining are a bit expensive, there are some less than desirable options and the temptation for some shops might be to use the cheaper alternatives. I have seen several heads now with a seal similar to the old Datsun L20B design and those simply will leak oil. Not to say this is what you have but worth looking at, those seals are 20% of the cost of the steel clad and ..well..worth every penny.

The $185 figure you mention is very low for a weld repair, valve job, guides, resurface and seals, by about $100-$150 locally and here in Oregon we are a bit lower than many other parts of the Nation. That alone makes me a tad suspicious.

One other possible is if the guides bores were damaged driving out the old guides?? This can create a channel outside the guide that will leak oil and that does fit your description perfectly since the amount of oil could be more at idle (maximum vacuum and volume/engine speed) than at highway speed.. That can happen and it has happened to us, the solution if you find this is to rehone the guide housing bore and install an oversize OD guide.....*EB