cones or sorbothane or both?

This is a question which cannot really be answered. As bizarre as it sounds, each of the isolation devices has a sonic signature. Aurios bearing sound different than navcom feet, and brass cones sound different than sorbothane. The only thing you can really do is try each of them and decide which one you like the best. Of course, that's not as easy as it might sound. If you can, borrow as many types as possible from your friends.

Do a search in the Tweaks/DIY forum at AudioAsylum.com

Some forms do a better job or a different job of dissipating energy. Nothing is perfect. Do a search on Neuance shelves here or on the net and you will find info on the direction I have taken, and do not regret, and have not fiddled with for a year or so now (which is saying a big something by the way).

Cones and sorbothane disks are based on two different theories. Although there are those who would claim differently, I believe you negate the effects of cones using sorbothane anything. A cone is a coupling device, sorbothane disks are a decoupling and energy absorption device.

A cone, by putting the weight on a very small point, makes whatever is on top of the cone vibrationally couple to whatever is under it. In other words, if you put a heavy speaker on cones on the floor of your house, the speakers act as if they are a much heavier object. That means that vibrational energy will have a smaller impact on the speaker itself, because the vibrational energy is attempting to displace a much greater mass (your house).

A sorbothane disk, on the other hand, is designed to decouple two things by absorbing vibrational energy and turning it into heat. In other words, if you have something that is vibrating one one side of the footer, the footer absorbs the vibrations instead of transmitting the vibrations to whatever is on the other side.

Thus, if you put a speaker on cones and put the cones on a sorbothane footer on the floor, you may couple better to the footer, but you aren't coupling to the floor. You might as well just use the footers.

So, if you are trying to prevent vibrations from one piece of gear on a shelf to get to other pieces of gear, pucks may be a better solution. If you are trying to keep things from vibrating at all, cones may be better. I'm a believer in cones myself. YMMV.