  Given two quantum memories for continuous variables (e.g., the collective
pseudo-spin of two atomic ensembles) and the possibility to perform passive
optical operations (typically beam-splitters) on the optical modes before or
after the storage, two possible scenarios arise resulting in generally
different degrees of final entanglement. Namely, one could either store an
entangled state and retrieve it directly from the memory, or rather store two
separate single-mode squeezed states and then combine them with a beam-splitter
to generate the final entangled state. In this paper, we address the question
of which of these two options yields the higher entanglement. By adopting a
well established descrip- tion of QND feedback memories, and a simple but
realistic noise model, we analytically determine the optimal choice for several
regions of noise parameters and quantify the advantage it entails, not only in
terms of final entanglement but also in terms of the capability of the final
state to act as a shared resource for quantum teleportation. We will see that,
for 'ideal' or 'nearly ideal' memories, the more efficient of the two options
is the one that better protects the quadrature subject to the largest noise in
the memory (by increasing it and making it more robust).
