Should the US and Candadian dollars be fixed to each other?

[Verily]

Amero. Economic nationalism is 20th-century.

[Verily]

Amero. Economic nationalism is 20th-century.

1 Amero = 1/100th oz. of gold, perhaps?

If you want to be buying things in hundredths of Amero-pennies, sure. There's not enough gold to sustain a gold-based currency in the long term.

[Verily]

Amero. Economic nationalism is 20th-century.

1 Amero = 1/100th oz. of gold, perhaps?

If you want to be buying things in hundredths of Amero-pennies, sure. There's not enough gold to sustain a gold-based currency in the long term.

Gold is, at present, about $700 per ounce. Consider that, until the early 1930s, the Mint issued 1-ounce Double Eagles, 90% gold coins worth $20 (traditionally US coins, except the penny and nickel, were either 90% silver/10% copper or 90% gold/10% copper). While the value of gold has gone up since then - gold's value has more than doubled in comparison to silver, for example - the value of the US dollar has plummeted to less than a tenth of its former value. Things are even worse with other currencies - a century ago, a British pound was at about $4, and a farthing (1/960th of a pre-decimal pound) of the era was worth more than a decimal penny is now.

a century ago, no coin smaller than the 1-cent/penny existed in the US. The dime, quarter, half dollar, and dollar were silver (the dollar was still a genuine dollar coin); there were gold $2.50, $5, $10, and $20 pieces (the quarter eagle, half eagle, eagle, and double eagle). A hot dog from Nathans, when it first opened in 1912, was a nickel. A bare-bones Model T Ford, in the 1920s, could be had for as little as $290 new.

1/100th of an ounce of gold is roughly $7 US. Its unlikely that you'll need any coin smaller than a mill (that's a tenth of a cent) anytime soon; heck the smallest coin will probably be a half-cent. 

An alternative is 1/5th of an ounce of silver (1 oz silver is at roughly $15, so that's about $3), but silver prices are much more volatile than gold prices. Its possible that a mixed-specie standard might be best - but that gets complicated.

The difficulty comes in printing currency. All currency printed must be backed by gold, which means that the amount of currency the US could print would be determined by how much gold we have stockpiled. We have a lot of gold stockpiled, to be certain, but not nearly enough to maintain anywhere close to as much money in circulation as there is now. A small supply of currency coupled with high demand means the value of currency (and gold) would rise uncontrollably, and within a few years we'd be paying for things in hundredths or thousandths of ameros (or dollars, if you like).