help with workbook-wide cell formatting

[ghendi]

Good day,

I have been looking for a solution existing on the forums but have come up empty handed.
I am looking for VBA code (from my understanding) in order to replace all cells within worksheets of my choosing with a different format, and vice-versa.

Detail: I have financials and models spread across the workbook covering more than a dozen worksheets. The company being modeled is European (using the Euro). It also has a base of operations in the USA. On the 1st worksheet ("COVER") I have set up a drop down selection to choose either € or $ (in cell $N$6). There is a second drop down list to choose expressed units (Millions, Thousands, Singles) in cell $N$8. I have the cell formatting used here:

[LIST=1]
[*]_($* #,##0.0_);_($* (#,##0.0);_($* "-"??_);_(@_)         —Used for top-line items ($, Singles)
[*]_(€* #,##0.0_);_(€* (#,##0.0);_(€* "-"??_);_(@_)         —Used for top-line items (€, Singles)
[*]_(#,##0.0_);_((#,##0.0);_("-"??_);_(@_)                  —Used for mid-line items (Singles)
[*]_($* #,##0.0,_);_($* (#,##0.0,);_($* "-"??_);_(@_)       —Used for top-line items ($, Thousands)
[*]_(€* #,##0.0,_);_(€* (#,##0.0,);_(€* "-"??_);_(@_)       —Used for top-line items (€, Thousands)
[*]_(#,##0.0,_);_((#,##0.0,);_("-"??_);_(@_)                —Used for mid-line items (Thousands)
[*]_($* #,##0.0,,_);_($* (#,##0.0,,);_($* "-"??_);_(@_)     —Used for top-line items ($, Millions)
[*]_(€* #,##0.0,,_);_(€* (#,##0.0,,);_(€* "-"??_);_(@_)     —Used for top-line items (€, Millions)
[*]_(#,##0.0,,_);_((#,##0.0,,);_("-"??_);_(@_)              —Used for mid-line items (Millions)
[/LIST]

Continued Detail: I have 2 cells ($S$6 and $S$7) on the COVER worksheet that have daily updated currency conversions. $S$6 is USD to Euro and $S$7 is Euro to USD. Based on the Expressed Units ($N$8), the Currency selected ($N$6), and it's respective conversion factor ($S$6 or $S$7) I am hoping the VBA code would scan all desired worksheets for cells containing a format previously listed above and convert it to the desired format, based on the criteria options on the COVER worksheet. If it's simple enough to understand, I could go into the VBA code to where the desired worksheets are listed and add/remove worksheets as needed. Or if possible, I could create a column list on the COVER worksheet starting from $L$12 (going down) with the exact names of the worksheets desired.

Thank you very much. I greatly appreciate any and all help.