You could search the archives on oar length, and oar position, lots of discussion of the past couple of years regarding what, where, and how. Good off-season talk.
I boat with commercials once in a while, and the approach to rapids is different. They go forward, and so they line up to run the rapid power forward. Even if that means side to side, they are still paddling mostly forward. With oars, it's a bit more like running the rapid side to side. Typically you'll line up before a rapid sideways, which allows you to move side to side easily until you choose the line, turn the boat and drop in. You'll also do your ferrying backwards most often. There were some technical rapids where I actually took a completely different line than the paddle boat, they lined up to power forward, and I'd sneak in to spin around and pull back. There's also a lot of angled upstream pulls during rapids to move the boat side to side while slowing it down.
This is the main reason paddle boats are slower, they run rapids power forward, and oar rigs run them power back/side.
Living in Montana, boating in Idaho