have the arrow be off-center by 30 percent, so that you can see more of what's in front of you

That's the first time I've heard arcs measured in percents.

And as long as you're going to the trouble (if you are) of rotating the map, you might as well have the initial offset be configurable. If you're worried about space ahead, then having it 90 degrees (or is that 25%?) offset might make even more sense. And then move the ``you are here'' point to the left, so that two-thirds of the screen is ``in front''.