The Field-Transformation Hybrid Monte-Carlo (FTHMC) algorithm potentially mitigates the issue
of critical slowing down by combining the HMC with a field transformation, originally proposed by
Lüscher and motivated as trivializing the theory. For the transformation, we use a single invertible
discrete smearing step inspired by the Wilson flow but which resembles a Jacobian-computable
generalisation of the stout smearing step. This is applied to a system with Iwasaki gauge fields and
2+1 Domain-Wall fermions. We have studied the effect of different smearing parameter values
on autocorrelation times of Wilson-flowed energies with different flow time. We have found a
reduction of exponential autocorrelation times for infra-red observables such as Wilson flowed
energy densities and topological charge densities when a larger value of the smearing parameter is
used. The autocorrelation times of local observables are computed using an approach akin to the
master-field technique, allowing us to estimate the effect of the field transformation with different
parameters based on a small number of configurations.