Standalone TLB Properties -- setting the Hot spot size ?

say if the R side of my screen is 12" tall,
then I'd like the toolbar to pop out only if I would touch it along in the first 3"- 4"
from the bottom of the screen?

Find the vertical resolution of your screen. Let's it be 768 pixels.
768 - 12"
X - 3"

So you need margin: 768 * 3 / 12 = 192 pixels. But you need the hot space at the bottom. So 768 - 192 = 576. Set the "Hot spot near margin" into 576 and toolbar pop out if you touch 192 pixels at the bottom.

Actually the margins are applied to the toolbar height/width not a screen resolution.