It seemed like a lot of Spock's Prime time flashed there, but how much was it? I'm wondering, if there was a general amount concerning only their friendship, or a whole lot more, because nuKirk should've had an inkling about Khan, shouldn't he have?
That will be decided by the requirements of future plots. If necessary, EVERYTHING, even if NuSpock doesn't know it...
The impression I got was that Spock Prime shared with Kirk what we saw in STXI and nothing else. I'm more curious exactly what Spock Prime told his younger counterpart in Into Darkness when asked "...how did you defeat him?"
Yeah, that would be interesting. I don't think "I recognized he didn't have much experience with three dimensional starship navigation, so Captain Kirk ordered to stop the Enterprise at a position with a negative offset along the Z axis to create a trap." would have been of any help.
"Well, I was dead at the time, but they told me I fixed the energizer just in time to warp away from a big explosion that was about to happen."
Same impression, pretty much - OldSpock gave nuKirk an info-dump on everything pertaining to Nero, red matter, destruction of Romulus, and trip through the wormhole, all with a nice I-just-felt-billions-of-Vulcans-die frosting.
Seeing the deal with whales, Praxis, etc--the two Spocks should really mindmeld and get all the information. This was, Quinto's Spock can inform Kirk on what the time line should be as a form of exposition to the general non-trekkie adventure audience. That saves time. As an easter egg, if Spock Prime should die in the JJ pictures, having him say "Remember" to Quinto during a meld would be a nice wrap-up.