The spread ratio of exchange given is not always correct, because prices change all the time. Not just index future i wanted to trade, but this also applies to all futures out there as well
Using IV is a rather curious choice... I am not sure what the underlying rationale for such a choice would be.
If it's for margin relief, surely you'd want to check what portfolio margin methodology your broker uses (it's not necessarily going to be the same as the exchange) and use that? I am not really sure why you'd choose to start with IV-derived weights, if you're just trying to obtain margin relief.
Let's just say you need 2.8 /CL for 1 /ES, its gonna required you alot more margin than /ES with 10% IV = $10000 /CL with 25% IV = $10000 so you only need to do 1 : 1 ratio, which effectively low down the required margin for a pairs trade
Pairs Trading of /ES and /CL usually by doing this, people weigh both these future by using Notional Value, but what im trying to achieve is using Implied Volatility to weigh both of this product. My question is should i using Implied Volatility/IV index shown in Option Statistic below of Thinkorswim Trade platform? Am i using the right IV?