I'm running the Soundsmith Zephyr on my Classic 3. Sounds great. Like you, I I was also looking for "on the warmer side of neutral" and it meets that description for me.
For more info, see my post here: http://forums.stevehoffman.tv/threads/cartridge-for-my-vpi-prime.454167/
For more info, see my post here: http://forums.stevehoffman.tv/threads/cartridge-for-my-vpi-prime.454167/