It doesn't matter what the spot price of gold or silver is. They can be compared to each other regardless of the currency. That comparison is the gold-to-silver ratio and is reported by Kitco
https://www.kitco.com/Gold_Silver_Ratio_Charts/gold-silver-ratio-charts.html .
Right now, the spot price of gold is 70 times as high as the spot price of silver. That means that you would get 70oz of silver for 1oz of gold (ignoring premiums and wholesale-to-retail spread). Sometimes, the spot price of gold is only 50 times as high as the spot price of silver. That means that you would get 1oz of gold for 50oz of silver (ignoring premiums and wholesale-to-retail spread). So, if you did both of those trades (by waiting for the sweet ratios to happen), you would get 20oz of silver for free. In reality, the spread narrows it to [high 60] <-> [low 60] rather than [70] <-> [50].
Towards the end of 2012, I traded 43x Ben Franklin halves (slightly over 17 oz Actual Silver Weight [ASW]) for 3x 1/10 Gold Eagles (0.3 oz of AGE). That was a fantastic deal because there is usually quite a premium on gold eagles. I recently traded those 3 tenth-eagles for a tube of silver rounds. 3 of those ounces were totally free from the trade<->trade of metals. The trade back was a better deal for the dealer than it was for me, but I was OK with it.
It seems to me that the opportunities for big moves only come every couple of years. The beauty of this strategy is that as you wait for the next move, you are holding precious metal. Whatever happens to the fiat currency is a don't-care. If your metal of choice is doing poorly against the dollar, that probably means that it is a good time to switch metals - you never lose if you pay attention to the dealer premiums.