The Milkovic 2 stage oscillator is really interesting, and I have always been intrigued by mechanical action devices. Watching the pendulum swing back and forth, I immediately thought how cool it would be to use a Bedini Pendulum with the device. It seems that very little battery power would be needed to keep the pendulum swinging, and that keeping the run battery fully charged should be no problem if switching is employed. Take a look at the smw1998a (Lee's) replication of the Bedini Pendulum, and envision it as replacing the pendulum of the Milkovic 2 stage oscillator, and see if you agree.
YouTube - Tic Toc

Rick