Sorry I left you hanging here, I’ll try to explain…
Similar to what I’m doing in my thread here and also more recently here. Trading the 2 currencies stretched furthest apart, looking for a retracement. But this is different from what you are doing because I’m not factoring in any correlation.
You can use this on any time-frame, but of course the question is when to buy and sell. If you looked at a few areas where prices separate you can probably come up with a min/max percentage/pip range that will trigger a buy/sell based on historical levels.
TradingView gives you the ability to overlay as many different instruments as you want. Here I’ve overlaid Gold and Silver/USD on the 5 min chart:
…but it’s not right, the Gold line (dark blue) has been compressed due to the difference in the price scales (I’m assuming). I like what @Trendswithbenefits did with his, that’s perfect.
I don’t know if this was of much help, but it’s good to throw ideas out and see what sticks.