  We discuss relations between uniform minimality, unconditionality and
interpolation for families of reproducing kernels in backward shift invariant
subspaces. This class of spaces contains as prominent examples the Paley-Wiener
spaces for which it is known that uniform minimality does in general neither
imply interpolation nor unconditionality. Hence, contrarily to the situation of
standard Hardy spaces (and other scales of spaces), changing the size of the
space seems %in this context necessary to deduce unconditionality or
interpolation from uniform minimality. Such a change can take two directions:
lowering the power of integration, or "increasing" the defining inner function
(e.g. increasing the type in the case of Paley-Wiener space). Khinchin's
inequalities play a substantial r\^ole in the proofs of our main results.
