I'm confused. Can someone explain these settings in small words for me? What's the difference between them?

Fuel Usage Speed Multipliers - How fast fuel is consumed.

Fuel Usage Multiplier - Fuel consumption multiplier.

Ok, so after re-reading the instructions, they are alittle vague for someone as inexperienced as me. I want furnaces to smelt faster and use fuel at a sloer rate. What are the right config settings?