Most of the time when I see a pod of carp cruising, I don't get one to break off and eat. But: exceptions happen. I think cruising speed plays into it, spawning cycle and who knows what else. Sometimes I think I sense pods that are actively searching for food versus just cruisin', but most cruisers are cruisin' and in my experience, fast cruisers just don't eat. I admit I haven't used a small damselfly nymph and probably should rethink strategy along this line. Maybe carry two rods (seriously Buzzy, seriously??).
Suspended carp, sun bathers or snoozers we call them, are surprisingly good prey for the fly fisher. We have some success fishing these guys from a boat fishing perched up on the casting platform (the bow

). They can be pretty light sleepers when sunbathing so accurate casts, longer than I use when wet wading (for the most part (exceptions again) and a fly that sinks but sinks slowly can trigger a grab.(1)
The whole tail up golden boner bit really is pretty rare, it seems mudflats are where I see this the most and I don't like fishing mud. Rooters without their tail up are more common in my home waters and they're my favorite. Rooters not facing me as I'm wading are what I look for but if a rooter facing me is really busy stirring up the bottom, there's always a chance he won't see my cast and if the fly lands nearby - just a foot or so to the side and I can drag the fly into his/her vision, that's a take I love to watch.
1. DK was poling my old Hewescraft, I was on the bow, we were slowing moving off a big "shoal" and into a weedy channel. I spotted a sun bather some distance away. I had an olive woolly worm tied on, my cast was perfect - the fly landed a few feet from the fish, a slow pull and the fly sank right by the fishes head. That carp woke up, chased and ate. The old fairy tale about not enough backing was almost true. Gone in a couple seconds and deep into backing. DK was about ready to start the motor to follow when I got the fish turned. That was 20 years ago, and I still remember it in detail.