Automated excel task - repost

Hi, This excercise may not even be able be possible but I am trying to prevent a very very time consuming manual task! I have a spreadsheet (attached). The sheet covers 72 people (U7:CN7) and the timeframe of 2014(Q8:Q372). Each day needs a certain demand ( Column R) and this means that column R needs an equal number of days shifts (D12) and night shifts(N12). For example 01/01/14 requires 7 made up of 7 D12 and 7 N12 etc etc throughout the year. Other criteria, each person needs to do roughly the same amount of D12 and equally the same amount of N12. So i wouldn't want to see one person doing 30 N12 and another doing 50 N12 etc. The stats panal at the top of theshift automatically how many D12 and N12 have been inputted into the sheet. Column S and T automatically counts the number of D12 and N12 shifts have been inputted into the orange cells. D12's should not be mixed in with N12 and hence a person should have a min of 2 N12 and a maximum of 2 D12 ina "block". What is filled in tab 1 should sort of explain. Also, wherever possible D12 blocks should be. followed by N12 blocks and then followed by D12 etc. Each person should have at leat 2 days off between each block of D12 or N12. Tab 2 is blank canvas. Macro maybe?