If I want to take about 60% of the Nifty 500's risk, what Sortino and Sharpe should I look for?

Great question — and the honest answer is that Sharpe and Sortino aren't the right dials for sizing risk. They measure how well a fund REWARDS the risk it takes, not how much risk it takes. The 'how much' dial is beta: a fund with a beta of ~0.6 versus its benchmark has historically moved about 60% as much as the index.

So the practical recipe is: filter for funds with beta around 0.5–0.7 (you'll find them among large caps, dividend-yield and some flexi/value funds), THEN use Sortino and Sharpe to pick the best fund among them. At any beta level, higher Sortino is better — above ~1.2 is strong for Indian equity funds.

One caveat: beta is backward-looking and shifts with markets. A low-beta fund in a calm period can behave differently in a crash — which is exactly why Sortino (downside-only risk) is the better companion metric. These are the lowest-beta flexi cap funds today: