Is there any way to stop chart imagery from scaling randomly?

Excel charts have this tendency to change size in a random way, an I need to
figure out how this can be prevented, either programmatically, or through
use of object options that I have somehow missed.

Example: Pie chart. Clicking on it to access some of the settings can, even
if nothing is changed, cause the pies to change their size, usually smaller.
This is especially true if some setting IS changed, and even more so if the
chart in question is accessed as an object placed within Word.

When I say "change size", I mean the imagery, not the size of the bounding
box containing the imagery.

The problem is worsened by the activity of grabbing one of the bounding box
corners and scaling the chart larger. Yes, the image grows, but after the
image is grown to the desired size, you cannot then reduce the size of the
bounding box without the image scaling down again, and it will be even
smaller then before. It is like a ratcheting effect.

Is there no way to specify or at least lock the size of the image,
independent of the box containing it? Is there no way to keep these things
from randomly changing their size?

My goal is to have two adjacent pie charts, comparing different data, but
coordinated in style, angle to viewer, 3D thickness, etc. Even if one pie
only has two pieces with labels and the other has six with labels, I want
the final product to show the overall pies to be the same physical size on
the page.

I also want them to print without reducing their size, and to come into Word
with the same smoothness of curves that they have when they are still in
Excel.

Is this too much to want???? Is there any definitive and affirmative
solutions to these problems?

Bill