I'm in the Europe/Berlin Timezone and I need to calculate a global volatility indication Monday to Friday at 12:00.
My portfolio can somewhat accurately represented by 60/30/10 S&P500, EuroStoxx50, and Nikkei225, and I need my volatility indicator to resemble that approximately.
These markets trade in entirely different time zones, and I want to combine the most up-to-date information at 12:00 in the Berlin timezone. So this info is intraday and near-realtime, but I could just use historical daily returns over 24h periods starting at 12:00:00. Basically use 12:00-prices instead of closing prices. I can either use historical daily prices, option implied volatilities, futures, it really doesn't matter.
Are there any 'best practices' to do this? I fear that my only choice will be to provide the latest vol index by timezone/market, and not combine them at all.
Bonus: How to treat dividends? Usually I use NET TR hedged in EUR, but I could work with anything else.
Thank you for your input.