In a document feeder with a superposed sheet input tray and sheet output stacking tray for feeding and then restacking print media paper sheets of variable dimensions, the lateral setting (repositioning) of the at least one variable position side guide of the input tray to the sides of the input sheets automatically correspondingly resets the corresponding side guide of the underlying output stacking tray, to reduce sheet scattering in the sheet stacking, especially skewed sheets. This may be accomplished by a simple direct mechanical integration of these respective side guides into a single repositionable component with upper and lower extending sheet edge guide portions.