The spatial flexibility of Extended Reality (XR) allows for personalized, context-aware organization of applications aligned with a user’s tasks and priorities. Notifications play a crucial role here, e.g., informing users of received messages they might otherwise miss. However, questions remain around how attention-grabbing they should be, how much information they should present, and how the presentation should adapt to the message’s context and content. While prior studies examined facets of message notification design, the impact of multimodal notifications and how they could be used holistically to support message awareness has not yet been explored. We address this by evaluating nine audio-visual notifications, investigating usability, interruptibility, preferences, and their use to inform of received messages. Our results show differing effects of multimodal notification designs and that individuals want notification modality and design to vary based on delivered message content. These results offer new insights into developing context-aware multimodal interaction strategies for spatial notifica¬tions and XR messaging.