Space needed for sellos in Santiago

[kennymandy]

Apologies if this question has already been answered, but where do you get sellos on arrival in Santiago?
For example, does the Cathedral issue a one?
More importantly, how much space do you need to have left in your Credential? I think I read somewhere that a Santigo sello is much bigger and covers 4 squares. Is this correct?

 

[Bradypus]

The last sello is made by the Pilgrim Office itself when you ask for a Compostela. It is placed under your personal details. You may also be given one in the last available square. The Pilgrim Office sello is not especially large.

 

[Anemone del Camino]

The Lugo cathedral has a huge sello. The one from Santiago is as anticlimatic as arriving in town can be. Quite a lesson in humility. Just one tiny square, a bit taller than wide.

 

[John Sikora]

if you're worried about sello space just glue a second or third passport together with the first. Works just find and you can put more than 3 a day into it for great memories