if I set a value to validate.validators.numericality.options.message, you can't customize the message when validating, using message or notValid. I would expect to still be able to provide custom messages event if I set a default one. This problem looks specific to the numericality validator, as I do not have this problem with the 'presence' validator.

I've tried to set the message in both the constraints and option object, without any luck

This is using the validate.single function.