I am not sure if I got your temple example right. What would be more useful after 4 wells: 4 temples in the first g.well or 4 temples in a row?
There's really no easy answer. In general, you want the most culture output to be on your front line, because that's what's competing with enemy culture. For that, you usually only have a few frontline planets and you'd ideally want a couple temples on each.
For your core empire, the only thing that's important is that they are covered by culture, and for that one temple for every few jumps will do just fine.
So a lot depends on the map layout. For a good enough rule of thumb, I would say you should strive to make sure all of your planets are in friendly culture. If it's spreading too slow for your liking in your core empire, build a couple more. If enemy culture is starting to creep up on your border planets, build a few more. Play it by ear, sort of, and you won't go wrong