I dig those Wisco rivers. Used to live in MN and loved swinging flies on that coast.
13 footers might be a little easier to learn on, but the OPST head is going to be a little issue, too. My impression of using them on switch rods is that the goal is for them to feel "Light." Constant motion in the cast, as they advocate, was tricky for me for the same reason... not feeling the load and blowing anchors. They are great when they work, but I prefer feeling the rod load up a little more.
Before you swap rods or something, maybe try a skagit switch (I like airflo, but rio
is great, too) in the size recommended for the rod. Take is easy (go slow) and you'll feel it load up a little better.
The airflo scout might kick butt on that rod, too. Same length as OPST, but weight recommendations that align with "trad" skagit recs. In my experience, maybe err on the light side with those. Maybe the same as "scandi" weight.
Since you don't need to dredge on those low gradient rivers, you might consider opting for a skagit head right in the middle of your grain window since you won't need to turn over gnarly stuff. T-8 should be fine on 90% of the water you swing. My go to was lightly weighted patterns (or unweighted) and a 5/5 iMow tip. That way you can swing some of that slow, tank water you used to get them on the pin in...
PS: Swing sculpin patterns, or white marabous. Both with lots of flash. You'll get smoked.