  Let $G$ be a complex reductive group and let $X$ and $E$ be two linear
representations of $G$. Let $Y$ be a complete intersection in $X$ equal to the
zero locus of a $G$-equivariant section of the trivial bundle $E \times X \to
X$. We explain some general techniques for using quasimap formulas to compute
useful $I$-functions of $Y\mathord{/\mkern-6mu/} G$. We work several explicit
examples, including a rigorous derivation of a quantum period computed
conjecturally by Oneto-Petracci.
