Compare fixation and permeabilization separately
Use one cell batch and vary fixation or permeabilization separately, keeping WGA input and acquisition settings constant. Include non-permeabilized samples to distinguish surface staining from intracellular sites exposed by treatment.
Judge against the imaging objective
For membrane outlines, assess continuity, cell loss and intracellular interference. For intracellular glycans, assess separation of the target region from background. Choose conditions that preserve morphology and the required signal.