Hi seacrest,
Adding or changing cells on a hidden sheet is just like with any other sheet, except that you must do it directly, without selecting any object in or on the sheet. For example to set cell B4 on worksheet Sheet2 which is hidden, instead of doing
Worksheets("Sheet2").Range("B4").Select
Selection = "Hello"
you must do
Worksheets("Sheet2").Range("B4") = "Hello"
So you see, it is actually easier.