Totally agree with @
dougfitz - if there is no room at the toe area when you are going downhill your toes will hurt.
Is there a reason why you want to wear 2 pairs of socks? Will you normally walk with two pairs of socks or is it only for Camino? If you are going to be investing in a good pair of hiking boots will you wear the same boots after wards with two socks?
You really to address these questions with a good reputable Camping, Hiking supply store - they will help you. Train with the boots with what you plan to wear so your feet get used to it before you go, including showering the night before your walk, vasaline etc. You also need to walk with your pack as the pack increases the resistance and puts more weight in your feet - room for soreness, blisters etc.