Brucks,

Maybe you tried this, but I only screwed my spikes in about 3/4ths of the way, and then adjusted each one (testing the wobble) until it felt stable. With the spikes not all the way in, you can move each one up or down. When it felt dialed in, I screwed the lock rings up hard to the bottoms of the speakers to keep the spikes in place.

The M80s DO have a very high centre of balance, so some instability is inevitable. But you can stop them from wobbling!