A client is using webform-CiviCRM for a contribution page. Due to pro-rating and other factors, each contributor needs to pay a unique amount - and thus the webform has the exposed "Contribution Amount" element that can accept an amount from a user.
How can I pre-fill this Contribution Amount using a custom field value? The webform Default Value can't be set to a token for a custom field that has the amount (returns "This is a CiviCRM currency field. Default value must be a number.", even if the field is an integer or a number.
It might also be possible to attach the $ amount to the URL as a parameter?