A sight that used to be popular on lever actions was a tang mounted peep sight like those from Marble Arms. One potential advantage of the tang mounted sight is that the elevation adjustment can be low enough that the factory front sight will be suitable, whereas you usually need a taller front sight when you install a receiver sight. Since the aperture of the tang sight is closer to your eye, you can choose a smaller aperture than you could with a receiver sight, which, in theory, improves precision, without loosing speed.