Quick and Dirty: take on-the-run 30 day trading range for each leg and then monetize each leg's value. For example, take the last 30 days of trading range for Silver, monetize it, do the same for Gold, then calculate your hedge ratio for Gold versus Silver accordingly.
You have to be very careful about inter market spreads - if the individual components are not highly correlated (>95% close-on-close) you will get smoked on cointegration. Even then - the disparate order flows between them can be a challenge. A great example of this is Gold vs. Franc where they trade in different sectors.
Intra market spreads (like Jun CL vs Sept CL vs Dec CL butterfly) none of this is a problem.
Many thanks Bone. But wouldn’t the hedge ratio and chart ratio be different?
The hedge ratio would be the monetised volatility of spread 1 / spread 2
but for the chart to make sense would there need to be a multiplier so they were equally weighted on the chart?
In the above example even though they both have an average monetary volatility of of about $1000 a day if I just have the chart as 1:1 the leg that only has a price of 0.68 barely moves the chart.
hope that makes sense. I have a lot of experience with intramarket spreads such as crude or Eurodollar etc. But wanted to branch out into some more exotic things.