Regarding the rings its dependent on the bore finish. If the correct bore finish is used with the correct ring choice there is almost an instant seat. The big issue with the cast iron rings is they are very brittle under cyl. press. and the spike from n2o will make the moly rings better for longevity.
You're probably right. I trust my machinest, and I'm going with moly rings. I just have had some bad experiences.
Kurt