Callawar, you will need to experiment with this. I'm not sure I understand the value of comparing the project date with the actual finish date. By definition, the project(ed) date is equal to the Actual finish date when a task is completed.
That said, the general format for calculating a difference of two dates is with a formula like this:
DateDiff("d",[Baseline1 Finish],[Finish])*480
Use a Duration custom field such as Duration1. Note the *480 which converts the result to days for display.
As an alternative you could use the function ProjDateDiff which allows you to specify the project calendar so that the difference.
Specify the indicators in the custom field dialog box to get the colours you want. The tests are applied in the order you list them until a match is found.
Graham