The present indicative (spiega) is often used in Italian to describe:
1) habitual actions: “He regularly explains…”
2) general truths or instructions: “Here is what the clerk does whenever…”
Timbro typically means:
Context tells you if it’s the device (stamp) or the imprint (the stamped mark).
You can say “il giusto timbro” or “il timbro giusto” with minimal change in meaning. Nuances:
Both are correct; post-nominal placement is more standard for adjectives describing qualities.
Yes. Each has a slightly different shade:
So:
Yes. Using “si sceglie” turns the subordinate clause into an impersonal construction (“one chooses” / “you choose”). That version:
Both are natural; the impersonal form can feel a bit more formal or abstract.