Finally figured out the conflict between Tobii SDK and SRanipal! For anyone interested, it turns out that having Tobii SDK active will automatically set "EnableEyeDataCallback" in the Vive SR Framework to 'false', even if you have checked the box in the GUI. I'm still not sure what's causing that, but if you go into SR_Anipal_Eye_Framework.cs and set EnableEyeDataCallback = true, this script @Corvus's script will work with Tobii SDK running.