@Di Burger Why not get a stamp from both places?? You will want to get the special credential for the San Salvador, only available at the
Albergue de Peregrinos Las Carbajalas, south of the cathedral. It is 3 Euro. I included a link for you to have a look at this huge albergue, south of the cathedral and essentially along the French Way, before it heads north to the cathedral. The credential is very nice, and you can see photos of it on my web page, on the
San Salvador. There is a lot more information on this page as well, as you want to get the special document in Oviedo to certify your accomplishment, called the
Salvadorana. We did not actually stay in the giant albergue, but wanted to be closer to the start of the San Salvador, near the Parador, in a hotel called the
Hotel Quindos. We didn't want to add a bunch of km to start the day, since the 1st day is plenty long enough! Have a wonderful trip. and if I can answer any more questions, let me know!