Isolation Cones/Bearings placement on CD Transport

I'm not sure about isolation bearings, but with spikes/cones/points, the ideal location is to place the 'vibration control object' dirlectly underneath the spindle, and also directly underneath the power supply. And for amps and preamps, the ideal location is always under the power supplies whenever possible.

I believe that weight distribution of the chassis does not really matter as much except in the case of safety where the component can more easily lose it's balance.

-IMO

Based on my experience with Golden Sound DH Cones. Two cones in the front will increase the width of the sweet spot. One cone in the front will decrease the width of the sweet spot, however, increase the depth of the sound stage.
Generally, I like one cone in the front pointy side up and two cones in the back pointy side down.

Put your main finger on the middle cone and move it topside. Do the opposite for bearings.

I second Stehno's post! Thats always been my understanding on placement too.

mostly what I use. My bearings device are not like yours since I use a DIY recipe ( Diyumas) but they basically do what other commercial devices do.

I would use one right under the spindle, where's more movement is taking place. The other vibrational point is the transformer.

BDiament, from Audio Asylum and maker of another devices, suggest an equilateral triangle and the most separate as posible position.

BUT..you should consider experimentation before deciding where to put them at the end. Make sure they are well balanced, the power cord doesn't make unneccesary preasure against the sides and the base where they will be seated are well balanced.