Going by sound works quite well, although I imagine not for Ed, but looking through is equally good, I find a light surfaced floor is enough if you're in a well lit room or outside. Easiest way I find to adjust is to tighten up one bolt a little, just with the long end of an allen key, then move the other side until quiet or by eye, then tighten that up the same, back off the other and do the same then evenly tighten up both bolts, maybe going back to the first if it moved a bit.
I left the bottom tight, loosened the top a bit and moved it in the direction I thought it was off. Removed much of the noise so clamped it back down again before it had a second chance.
Going by sound works quite well, although I imagine not for Ed, but looking through is equally good, I find a light surfaced floor is enough if you're in a well lit room or outside. Easiest way I find to adjust is to tighten up one bolt a little, just with the long end of an allen key, then move the other side until quiet or by eye, then tighten that up the same, back off the other and do the same then evenly tighten up both bolts, maybe going back to the first if it moved a bit.