Sounds like a very nice outing, you definitely got their attention!
Although I certainly don't know if this is the case, one of the things that reduce solid hookups is a sag in the line from the current pushing the line into a down current arc between the rod tip and the fly. You might try mending upstream a bit and letting the fly lead the drift downriver slightly.
If the downriver swing was an important part of the presentation, then a technique common to salmon fishermen in the British Isles (and more recently steelheaders) is to lead the fly in a submerged "grease line" swing. In this approach, the rod ends up "pointing to the trees" by the end of the drift. In other words, the rod is led to maintain a workably taught line so it ends up pointing downstream and inward toward land by the end of the swing. This angle causes the fly to lodge in the corner of the fish's mouth, improving hookups when the line leads the fly down and across the current.
Hmmm... you just made me think of a neat tool for the vest - a re-barbing tool!