Did the Portuguese from Porto to SdC comfortably in 12 days and that was in the heat of summer - my companion was a schoolteacher so it had to be done in the summer vacation.
We walked along the coast until Redondela and then struck north.
The bit along the beaches where you walk on wooden boardwalk can be tedious and, as mentioned above, the Portuguese
do love their pavé stone walkways - as tiring on the feet as the tiles the Spanish use in their towns and cities.
If I were going to do it again I'd stick to the same itinerary (Matosinhos - Via do Conde - Esposende - Viana do Castelo - Caminha - Oia - Baiona - Vigo - Redondela - Pontevedra - Caldas de Reis - Padron - SdC) but stop off for a rest day in Pontevedra simply because I thought it a lovely town.
One tip though - don't make the same mistake we made between A Guarda and Oia and walk the main road; it is a never ending uphill drag in some places:
you can walk a greener, softer route between the shore and the highway through smallholdings and vegetable patches
Bom caminho!