G145: Ensuring that a contrast ratio of at least 3:1 exists between text (and images of text) and background behind the text

Refer to technique G145:
http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/G145.html
Summary of Issue: Note the following two observations:
1. Under description, the sentence "This technique relaxes the 4.5:1
contrast ratio requirement for text that is at least 18 point (if not bold)
or at least 14 point (if bold)" makes a case about the font size when text
is presented over a background. It is quite clear.
However, the following para, "If the background is a solid color (or all
black or all white) then the contrast ratio of the larger-scale text can be
maintained by making sure that each of the text letters have a 3:1 contrast
ratio with the background" does not give any indication of the font size.
What does "larger-scale" text mean in this situation? Can a font size be
used as baseline?

2. Para 3, "3:1contrast" needs a space.

Comment (Including rationale for any proposed change):
For #1, provide clarity on "larger-scale" text used in the scenario.
For #2, provide a space between the "3:1" and "contrast."

-Devarshi