What's the best approach for choosing between 'ovo' and 'ovr'?

For small datasets, 'ovo' can be beneficial due to its lower computational cost. For larger datasets, 'ovr' is generally preferred for its efficiency. You might need to experiment with both methods and evaluate their performance using appropriate metrics (e.g., accuracy, precision, recall, F1-score) on a validation set to determine the best choice for your specific problem.