I've been watching the trade ratios between the top 4 PM's for a number of years...
Right now, the Gold/Palladium Ratio has risen to 2.47:1
My trigger point is 3:1, but whenever I see a ratio start to get close to a trade trigger number, I consider making a trade.
the normal ratio is about 1.5:1
lowest below 1:1
highest 5:1