We propose specular NR measurements during deposition of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) using potentiostatic (PS), potentiodynamic (PD) and galvanostatic (GS) electrochemical control functions. These protocols are known anecdotally to generate polymer films with different characteristics, but the structural/compositional reasons are not known. The experiment will provide this information during and subsequent to film growth. We recently performed one part of this programme (at the ILL) using hydrogenous monomer (h-EDOT) in deuterated solvent (D2O): the NR data show variations between PS-, PD- and GS-derived films. To quantify these in terms of solvent volume fraction, film homogeneity and surface roughness we will perform complementary contrast variation experiments using d-EDOT (now available) and H2O. The outcomes will impact device design.