The first picture, Saint Peter's clock, had such sharp lighting that even while using a spot light meter (which was not so spot as I was several hundreds of meters away so the 1° angle covered a "large" area) I had to bracket some 0.5 EV to be sure not to burn the highlights. This is one of the few occasions, and the only one I remember, where I did bracket exposure. I remember I always was quite in the vicinity of EV4@100 ISO.
* Besides bracketing, that is.
The general experience I have now is that EV4@100 ISO is very likely to work well with slides. Walking around with a negative film I would use EV4@100 ISO without using any light meter.