Can we leverage custom fields for Sales Forecasting in Redwood?

Summary:

We have set up Sales Forecasting in Redwood on the basis of Organization Hierarchy. Territory Management has not been implemented on our project. With regards to this, the question is - can the users forecast on the basis of a custom field value on Opportunity Header? E.g. Estimated Ceiling Amount = $124,000. We're trying to find a solution where we can set up a custom field to have the sales team add estimated ceiling value, without needing to add Opportunity Revenue lines, and then be able to forecast upon that estimated ceiling value.

Any thoughts would be welcome.

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