  Let $A$ be a quaternion algebra over a number field $F$, and $\mathcal{O}$ be
an $O_F$-order of full rank in $A$. Let $K$ be a quadratic field extension of
$F$ that embeds into $A$, and $B$ be an $O_F$-order in $K$. Suppose that
$\mathcal{O}$ is a Bass order that is well-behaved at all the dyadic primes of
$F$. We provide a necessary and sufficient condition for $B$ to be optimally
spinor selective for the genus of $\mathcal{O}$. This partially generalizes
previous results on optimal (spinor) selectivity by C. Maclachlan [Optimal
embeddings in quaternion algebras. J. Number Theory, 128(10):2852-2860, 2008]
for Eichler orders of square-free levels, and independently by M. Arenas et al.
[On optimal embeddings and trees. J. Number Theory, 193:91-117, 2018] and by J.
Voight [Chapter 31, Quaternion algebras, volume 288 of Graduate Texts in
Mathematics. Springer-Verlag, 2021] for Eichler orders of arbitrary levels.
