  Many current stellar evolution models assume some dependence of the strength
of convective core overshooting on mass for stars more massive than 1.1-1.2
solar masses, but the adopted shapes for that relation have remained somewhat
arbitrary for lack of strong observational constraints. In previous work we
compared stellar evolution models to well-measured eclipsing binaries to show
that, when overshooting is implemented as a diffusive process, the fitted free
parameter f(ov) rises sharply up to about 2 solar masses, and remains largely
constant thereafter. Here we analyze a new sample of eight binaries selected to
be in the critical mass range below 2 solar masses where f(ov) is changing the
most, nearly doubling the number of individual stars in this regime. This
interval is important because the precise way in which f(ov) changes determines
the shape of isochrones in the turnoff region of 1-5 Gyr clusters, and can thus
affect their inferred ages. It also has a significant influence on estimates of
stellar properties for exoplanet hosts, on stellar population synthesis, and on
the detailed modeling of interior stellar structures, including the calculation
of oscillation frequencies that are observable with asteroseismic techniques.
We find that the derived f(ov) values for our new sample are consistent with
the trend defined by our earlier determinations, and strengthen the relation.
This provides an opportunity for future series of models to test the new
prescription, grounded on observations, against independent observations that
may constrain overshooting in a different way.
