Just in case someone skips to page two and misses my response:
Your answer is here:
https://forum.freecapitalists.org/t/quick-shift-to-gold-standard-question/20807/4
This is the comprehensive response to Gold Standard Questions. In the list of links you will find the question of whether there is enough gold for a gold standard. From what I understand, the question is supply and demand (ie, price of gold relative to federal resevre notes goes up).
Mises explains that even an ounce of gold would be theoretically enough.