Quote from ben111:
@hlpsg
Sorry for the delayed answer.
I don't want to hedge the vol risk between the two months. At the expiration of the front month only the back month implied volatility matters. Is it higher than at entry the payoff is worse than modelled :-(
Is there any way to compare VIX options with SPX options (eg. SPX vega <-> VIX delta, ...)? Or are they just two different underlyings and you can't compare their options?
i see. to hedge the vol risk you need to spend some of your capital to put on another similar (meaning long gamma) strategy that profits from a rising IV, and rehedge whenever the portfolio's Vega gets above a certain absolute threshold (+ve or -ve). A straddle is one simple example. I'd recommend this over using VIX derivatives because the correlation, as others have mentioned, may be far from perfect, and you might not get the hedge when you most need it.
On your 2nd answer, yes there's an easy way to model different underlyings together in TOS. In the analyze page just click on "Portfolio, beta weighted" instead of "Single".
Hope this helps.