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).