I use the following chart to help me find helmets as I have a narrow oval head, and most of the popular (read: affordable) helmets are round.
https://www.webbikeworld.com/motorcy...nternal-shape/
Looking at the chart, the Airoh Aviator is slightly narrow, which leads me to believe that you have a round(ish) head, so you probably want to look for a helmet in the neutral to slightly round sections. It looks like the Airoh Terminator is a rounder shape, and it's still pretty light (as far as dirt helmets go).
What size is your Airoh? You know, just in case it's still in good shape and you might be considering selling it...