I found a huge difference between the hopping foot, which I think you are using, and the gliding foot, which is what happens when you "break" the foot a la Leah Day. Although, I bought a FMQ-ing foot that went with my machine, that glides over the surface of the fabric. I also found the slider does make a big difference and I can't work well wihtout the gloves. I cut the index fingers off so I can still work wihtout having to take the gloves off to do things like re-thread my machine etc.
For me, each type of FM I do has a speed that is perfect for it. When I do pebbles, I go at a different speed and move the fabric at a different speed than I do when I do meandering. It's all personal preference.
You're way ahead of me with the spirals. Those things are my downfall...cannot do them, but I'm still trying!
Watson