I've been wanting to ask this question before but couldn't decide where to post so since the topic of 'large' and 'small' settings is coming up in this post I'll try here.

Is there a rule of thumb as to when you should set your speakers to large or small?

For instance I have a pair of PSB Stratus Silveri for the mains and a pair of PSB Image 4t as the surrounds. The center is a PSB Image 8c.

I'll assume the center should be kept small.

If I don't have a sub should I set the the mains and surrounds to large?

If I do have a sub should I set these to large or small? Does it matter?

Under what conditions am I risking my speakers to damage? I play them loud sometimes but I don't believe it's unreasonably loud (of course one person's loud is another person's NASA launch). I haven't shattered any glass yet.

Is there information in the speaker's specs that I should use a guideline. Be nice now, if this is a naive question.

Mark