Using sales objectives to calculate daily sales rates by month

Attached is my workbook – I am currently trying to use sales objectives to establish a ‘daily sales rate’ objective for each month, by region, using the # of selling days per month.

The ‘daily sales rates’ for each month (by region) for last year are highlighted in blue – and I’m trying to fill in the yellow cells.

Please note how the values in green are calculated (beginning in cell O39). I’m hoping to use my objectives highlighted in orange to reverse this process and fill in the yellow cells. I know that solely doing this could result in countless solutions but since I have the % increase by region (D7:D18) I think there may be a way to logically work this out.

Thank you in advance for your input.