ToolBar Captions and Button Size

I gotta be missing something here.

I set up a TToolBar of height 45 containing tbsButtons of height 43 and
width 45.
AutoSizes on the TToolBar and Buttons are False.
TToolBar.ShowCaptions is False.
The buttons are squarish - just as I want them.

As soon as I switch TToolBar.ShowCaptions to True,
the buttons all become long and narrow; height 36 and width 65.

I wouldn't mind so much, but now I can't fit all my buttons on the
TToolBar.

How can I set the button dimensions myself?

Thanks,
Graham