Highrez

I use a Logitech Trackman Marble, and I bound the right small button to act as a middle mouse button when clicked and as a scroll wheel when held. I use the "Change movement to scroll" functionality, and I think it works like a charm. That said, it doesn't work that well in games. Typically games scroll too quickly, and I can't always change the scrolling speed. Is there a way to make it work more like discreet scrolling somehow? So that it can be less sensitive, so to say.

EDIT:

I've played around with the settings some more. It's very easy to get it to behave, actually, so here's my solution so far.

Altering scrolling behavior

1. In the Scrolling tab I've changed the "Lines to scroll using the scroll wheel" to 1.
2. In the "Change movement to scroll" settings I amped up the scrolling sensitivity to 15. I've also locked scrolling to the Y-axis, but that's a preference thing. I feel like the scroll wheel behaves better if it's locked to one axis. YMMV.

I also had another solution that's possibly more precise:

Clicking to scroll

For this solution I dedicate a button to just scrolling. Interestingly the regular "Mouse Wheel Up/Down" actions didn't work for me, so here's my take. I'd set up a button as follows:

1. Use "Button held" for the button in question.
2. Set Normal Click to "Simulate Keystrokes" with the following output: {MWDN}
3. Set "Button held for 150ms" to "Simulate Keystrokes" with the following output: {MWUP}. Set it to repeatedly send the output while the button is down (option 6) and auto-repeat with an interval of 150ms.

It's a little more precise, though it does require more clicking.