I have a couple packs of them at the house here.. I bought them when I was hot loading the Black Diamond XR and the Disc to see if they made a difference. They really did not.

In the case of a hollow based conical, you could always try a wad, and then fill the hollow base with a lube. The heat will blow it out, but the lube will make the conical base expand better.

If you want to try some of them sub bases, let me know...