Hi
OK. There is a sort of work-around for this but you will need a mouse with a wheel.
Click the green Plus in the overlay track and enter the text you want to display. Click the respective arrow in the position matrix square so it dispays in the position where you want.
Now slide the size slider back to the left to reduce the size of the text. Make sure the slider is the last item controlled by the mouse or this may not work.
Now roll back the wheel a notch at a time. The text will enlarge a step with each notch. (Rolling forwards will reduce the text in size.) Count the notches used to get the size of text required and do the same process for each batch of overlay text.
It's probably the best you will get without numerical font size values.
Nat