I just got mine today. I do my chisels at 30 degrees, so that was fine. Next time I have it set up I’ll look into greater than 30. I used a angle-o-meter to set my angle, zeroing the meter on the plane and then setting the arm. I didn’t pay attention to the marks on the slider.
I, too, wish the jaw was wider. I clamp a bunch of stuff together to make a jig to do the planes, but now can scoot right through the chisels.