Cryo-transmission electron microscopy (cryo-TEM) is ideally suited to determine the size and shape of vesicles and, after post-acquisition computation, resolve high resolution 3D density maps. Membrane thickness from cryo-TEM is usually measured between the outer edges of the contrast interfaces in images without consideration of the hydrophobic core. More detailed information can be obtained with single particle analysis (SPA), which is more commonly used to determine structural features in proteins. In SPA, multiple instances of the sample are imaged aligned, classified and combined to give a higher-resolution image whereas cryoelectron tomography (cryo-ET) collects multiple images of the same specimen are taken at different angles, which can then be reconstituted into a 3D volume representing the same. Besides EM techniques, SAXS is an ensemble technique that has been used to confirm the size and shape of vesicle samples and the average electron density profile (EDP) of lipid membranes, unveiling, under optimised conditions, the membrane thickness with a precision of a few Ångströms. However, the resultant scattering pattern is not always straightforward to model without some a priori structural information that constrain model fits to physically relevant solutions. While cryo-TEM and SAXS are powerful techniques on their own, their combined use offers several advantages as the information gained from one technique informs and helps optimise the other. For example, fully reconstructed 3D structures obtained using cryo-TEM have been used to obtain theoretical SAXS curves, which can be compared to experimental SAXS profiles. Therefore, the analysis of SAXS data can be refined with cryo-EM data to give the most probable ensemble structure. Here, we combine these techniques to provide high resolution membrane structures in hybrid vesicles and show the coexistence of two membrane thickness populations in hybrid systems. This bimodal bilayer thickness distribution, in what are known to be well-mixed membranes, implies that structures of intermediate membrane thickness are energetically unfavourable.