Attention Guiding Techniques (AGTs) are an important design component of head-mounted Augmented Reality (AR) assistance systems for industrial work. By directing users to targets, AGTs can improve search efficiency. At the same time, however, guidance can narrow the user’s attentional focus and increase the risk of missing safety-relevant environmental events. This user study examined how different AGTs affect search efficiency, mental effort, and change detection under dual-task conditions. Participants wore AR glasses and searched for virtual target objects while simultaneously monitoring for changes during the task. These changes occurred within the virtual environment and consisted of shape changes in virtual objects. Four experimental conditions were compared: a text-cue-only baseline, in which participants received a textual indication of the target object without any additional visual guidance, and three AGT conditions: Highlight, 3D Arrow, and Attentional Funnel. Overall, the results suggest that the Attentional Funnel provides the most favorable solution when efficient target selection is prioritized, whereas Highlight appears to be more suitable when sensitivity to concurrent environmental changes is critical. These findings point to a trade-off between strong attentional guidance and broader attentional openness under dual-task conditions.