ENHC has no effect on this: use your normal index...
Victor V. Romeo,
If you think about it for a moment, you'll realize that, even in an American-style game, the Insurance decision is essentially a "No Hole Card" decision, since the player makes his decision before the dealer checks for BJ... same as in a European-style game.
Thus, just use the normal index for insurance and, naturally, even-money.
Hope this helps!
Dog Hand