Thanks for the tips. I'm probably going to use the radiator flush method with the expansion tank. Not in a hurry.

I wonder if a two-person operation with one monitoring the drain and the other keeping the sealed funnel, with shut off valve, on the expansion tank topped off with distilled water would avoid the introduction of air... wouldn't any air escape through the bleeding hole if done that way?

I guess the last fill with pure coolant would have to be done the standard way?