Coconut oil is an MCT so can actually be used very quickly by the body. It’s not processed in quite the same way as other fats.
I genuinely doubt the OP can achieve measurable difference in weight/fat loss by focusing on fat oxidation during long rides.
Study after study has shown that fasted exercise does not result in a greater fat loss when calorie intake and exercise time and intensity were equated.
And (not aiming this at anyone in this thread) people need to remember that energy balance (calorie surplus/deficit) takes place over days or weeks, not merely a morning.
Eat in a modest deficit, concentrate more of your calories and carbs around and in the workout, drink plenty of water, and weight loss will come. Throw in a bit of resistance training to maintain muscle mass and job done: simple. N.b.: simple does not = easy.