Sorry to break it to you, but there is no "BEST" Kettlebell workout for fat loss.
However, there is a "BETTER" Kettlebell workout for fat loss.
Your Kettlebell training should gradually progress to become more challenging and more intense.
So how do you make a workout become more and more challenging? Well, I like to set little mini challenges up for myself.
I'll start off with a basic workout, and then I'll design a more advanced version of that workout.
The idea is to gradually add more work to the first workout until I hit my target, advanced workout.
Here is an example: Basic Workout: 3 rounds of:

• Kettlebell Snatch, 5 reps
• Kettlebell Turkish Get Up, 3 reps
• Rest 1 minutes

Advanced Workout: 5 rounds of:

• Kettlebell Snatch, 8 reps
• Kettlebell Turkish Get Up, 5 reps
• 2-Hand Kettlebell Swing, 12 reps
• Rest 1 minutes

That advanced workout is pretty tough.
Especially if you do it with a 50lb Kettlebell.
So how can we steadily transition to the Basic Workout to the Advanced Workout? Here's a sample progression plan:

• Week One - Perform 4 rounds
• Week Two - Perform 6 Snatches, and 4 Get Ups
• Week Three - Add in 10 Repetitions of 2 Hand KB Swing
• Week Four - Perform 5 Rounds
• Week Five - Perform the Advanced Workout

Your progression may take longer than 5 weeks.
But the bottom line is that a) You've created a decent 6-week training program in a matter of minutes, and b) you've been challenging yourself so you'll be stronger, faster, and leaner from where you started out from.
Do this for two other workouts, and you have a great, 3 day per week Kettlebell program that just takes 20-30 minutes per session.
Keep yourself educated with the latest exercises and try to invent some new ones along the way.