The original guitar solo track is on top, the edited track is below it, and the delays have been recorded on the track below that.
If you want to add delays—particularly long delays—onto just a few notes in a phrase, here’s a tip:
Rather than continually riding or muting an effects send, create a duplicate of the track you want to add delays to and edit out all of the parts that you don’t want to have delayed. Then, use that track to feed the delay instead of the original. You get the original track unaltered, along with delays only on particular notes. Blend in or discard the duplicated track to taste. And if you want to keep the delays from conflicting with the original notes, try rolling off the low and low-mid frequencies, and perhaps adding some sort of modulation, such as chorus.