I open pretty light, but I don't open this hand. My 11's that I open 1st/2nd will either be AK suits or have somet sort of distributional upgrade. Having said that, there are essentially 2 approachs here, both of which are playable, just as usual you need to be on the same page with partner. Either 2NT promises extras, and the 2♠ rebid does NOT promise a 6th spade, or 2NT does NOT promise extras and 2♠ *does* promise a 6th spade.