How to make Workbooks smaller / Excel performance better (#2)

Here are my questions:

1. Is there any way I can just cancel the cells not used? The default max ranges in an excel spreadsheet is like 65536 rows by 256 columns, so the idea would be to limit the default max range to my max used range. The way I have it set up is that the window doesn't even move (the pane is frozen), so I have no use for all the cells surrounding the first viewable cells on the screen.

2. If this is not possible, even if I delete the rage of cells to be the actual used range of cells(as the fix by Otto mentions), is the file size affected by all the rest of the not used cell ranges?

3. I also have shapes as buttons to navigate through the workbook, is that increasing the file size significantly? how can I compress the buttons?

4. Essentially I just need the workbook to not stall when being used. How else can I help it.

The following is a great FIX posted a few years ago, but... I need more...

Link to quoted solution:
http://www.excelforum.com/excel-gene...ce-better.html

Quoted solution by: Otto Moehrbach
Excel has a problem with determining the range, call it used range, in a
sheet. For instance, do this:
Open a new blank file.
Type something in cell E10.
Select A1.
Now do Ctrl - End. This should take you to the last cell in the used range.
Note that Excel selects E10. Good.
Now clear E10.
Select C5 and type something in that cell.
Select A1.
Do Ctrl - End again.
Notice that Excel selects E10.
You know the last cell in the used range is C5. Excel thinks it's E10.
The size of the file is due, in part, to what Excel thinks is the used
range.
The above example is over a small range. If the above were to happen over
thousands of rows and hundreds of columns, the difference in the size of the
file would be significant. Even huge.
Go to each of the sheets in this file you have and do Ctrl-End and see how
Excel's idea of the used range and your idea of it differ.
What you have to do, if this is a problem, is delete all the columns after
the real last column and the same with the rows. Then save the file, close
the file, reopen the file, and see what you have in size.
There are ways to automate this process of resetting the used range if your
file has many sheets.

Thanks bunch~~

Alright, what about the Buttons(Shapes), is there a way to compress them?

The help, much appreciated.