In the 2.5.8 Understanding doc, Figure 1 uses the phrase, "Where targets are a 24 by 24px square (and larger is better)..."
I'd suggest to use "at least 24 px" consistently in the Understanding doc where the sentence is suggesting a size for a target; 24 px is the threshold.

"And larger is better" seems like awkward grammar (is it not "or"?) and vaguely subjective, whereas just "or larger", or "or larger for [reason: ease of activation]..." or "at least 24 px" seems more straightforward.