best way to customize dictionary for hand written digit recognition Model (with SAR)

[IacopoFerrari]

Hello everyone,
My goal is to limit the character dictionary to exclusively include numeric values for my specific use case. I have consulted the FAQ, which states, 'In MMOCR 1.0, you only need to modify the config and point the Dictionary to your custom dict file.' Unfortunately, following these steps, configuring a dictionary with just numeric values, significantly worsens the model predictions.
Can anyone suggest a proper way to achieve this?