Assuming the goal is fat loss, 200mg is a perfectly effective dose when following a polypharmacy model with multiple drug pathways contributing to the desired end result. Although this is not what I would recommend, you’d likely need more than that to see noticeable effect if using L-Carnitine alone. 200mg of l-carnitine + 1.5iu of GH for example would be a great synergy of FFA mobilisation + transport. For fat loss I would simply recommend remaining fasted for the duration of time you want to accelerate the transportation of mobilised fatty acids. So for example, the duration of your fasted cardio, or the 2-3 hour window that GH will be mobilising FFA’s for. For hypertrophy, dosages at >1000mg potentially cause issues with FFA dumping, so I wouldn’t recommend going that high. I don’t see issues with 200-600mg/day, but I have never seen a case for nutrient transport that has warranted >200mg in my experience. Pre-workout to aid in glucose disposal is smart idea.