The magnetic ground states of geometrically frustrated pyrochlores are highly sensitive to the presence of defects. The stuffing of rare-earth ions on titanium sites has recently been proposed to be the dominant defect in as-grown Yb2Ti2O7, leading to a strong sample dependence of the magnetic ordering at low temperature. For spin ice, it has also been suggested that these defects play a role in suppressing the monopole dynamics at low temperatures. We propose to determine the defect structures in deliberately stuffed Yb2+xTi2-xO7-x/2 using diffuse neutron scattering. The results will be compared empirically with those of diluted Yb2-xTi2+xO7+x/2 and as-grown Yb2Tb2O7, and with the predictions of DFT. Determining the nature of these defect clusters will allow us to identify the magnetic defects and better understand magnetic ground states and monopole dynamics in pyrochlores.