  We prove precise growth and cancellation estimates for the Szeg\H{o} kernel
of an unbounded model domain $\Omega\subset\mathbb{C}^2$ under the assumption
that ${\rm b}\Omega$ satisfies a uniform finite-type hypothesis. Such domains
have smooth boundaries which are not algebraic varieties, and therefore admit
no global homogeneities that allow one to use compactness arguments in order to
obtain results. As an application of our estimates, we prove that the Szeg\H{o}
projection $\mathbb{S}$ of $\Omega$ is exactly regular on the non-isotropic
Sobolev spaces $NL_k^p({\rm b}\Omega)$ for $1<p<+\infty$ and $k=0,1,\ldots$,
and also that $\mathbb{S}:\Gamma_\alpha (E)\rightarrow \Gamma_\alpha({\rm
b}\Omega)$, for $E\Subset {\rm b}\Omega$ and $0<\alpha<+\infty$, with a bound
that depends only on ${\rm diam}(E)$, where $\Gamma_\alpha$ are the
non-isotropic H\"older spaces.
