With very high magnification (2X - 5X) it has been troublesome to light the subjects since the lens shadow often gets into the photo. If it does not, then the subjects end up poorly lit or backlit.
So what are good ways to light macro subjects with off-camera lights?
There are obviously on-camera (specifically on-lens) solutions but they are expensive, unflattering and inflexible. What I am looking for it an off-camera solution that is easy to adjust precisely but illuminates enough to be able to shoot at small apertures (but not beyond the diffraction limit) and low ISO.