If the slider is the white sheet of vinyl that keeps the static from building up - IT MAKES A HUGE DIFFERENCE. I am in a FMQ class right now (so far 3 out of 8) and using this sheet keeps the motion going. Not using the sheet sometimes results in a herky-jerky motion due to static.
Gloves are personal preference. There is a new type of glove that has a very thin hand with the grippers only on the fingertips. See if your LQS will let you try them for fit and comfort.
I have been practicing FMQ and found that I have better results when I practice the pattern on paper or repeating it with my finger on the table. Big difference!