Having had a look around, it seems the Spanish army was the size of the Belgian and the quality of the Ottoman in 1914. This was even with some national service. The country was very unstable, neutral because it was split between the 2 sides, and suffered increasing strikes and social unrest, to the point of military coup even without joining in the war.
In short, the present force pool seems about right for the army. NM would be very low and revolution / civil war likely.