Those are great fish! How long is that Spey rod? What kind of blank was it built on? I would love to get into a light weight Spey rod. (4/5/6) sounds ideal! But I don't think a high end rod is in my budget for a while. I can imagine how effective a nice long rod would be for fishing the way you do.
In the past I've spent some time swinging very light jigs on my flyrod with a spinning reel loaded with 4 pound test. Jigs were 1/64th and 1/80th and constructed with a lot of marabou and hen feathers. The longer the rod the better for good control.
You mentioned your success on the Maitland with smallmouth. That river is on my list for the upcoming season. Have you tried the Saugeen anywhere above Denny's dam?
I've been tying up a storm lately making some wonderfully mobile streamers and leeches. I can't wait for a chance to start flinging them. If you go to the Credit at this time of year on a weekend do you encounter many other anglers.? I am an occasional teacher so I can pick my spots and I've only been through the week.
Were you hitting those smallmouth on the Maitland in the spring or fall? I've heard of that phenomenon before; while targeting steelhead guys were picking up a lot of smallmouth. They must travel or hang in schools. I once caught smallmouth that size one after the other in an inlet to a lake in the Algonquin area. One thing for sure whether it's a steelie or a smallie you know it's going to jump and give you a heck of a fight. That's why they're my two preferred species especially on the flyrod.