  Quantum gravity effects in effective models of loop quantum gravity, such as
loop quantum cosmology, are encoded in the choice of so-called polymerisation
schemes. Physical viability of the models, such as an onset of quantum effects
at curvature scales near the Planck curvature, severely restrict the possible
choices. An alternative point of view on the choice of polymerisation scheme is
to choose adapted variables so that the scheme is the simplest possible one,
known as $\mu_0$-scheme in loop quantum cosmology. There, physically viable
models with $\mu_0$-scheme polymerise the Hubble rate $b$ that is directly
related to the Ricci scalar and the matter energy density on-shell.
Consequently, the onset of quantum effects depends precisely on those
parameters. In this letter, we construct similar variables for black to white
hole transitions modelled using the description of the Schwarzschild interior
as a Kantowski-Sachs cosmology. The resulting model uses the $\mu_0$-scheme and
features sensible physics for a broad range of initial conditions (= choices of
black and white hole masses) and favours symmetric transitions upon invoking
additional qualitative arguments. The resulting Hamiltonian is very simple and
at most quadratic in its arguments, allowing for a straight forward
quantisation.
