Good tips, especially the find your IPD was new to me. In regard of the fan: If your problem is mainly the heat of the HMD there are those "neck fans", which are simply 2 adjustable fans with a kind of neck brace between them which contains the battery. Yes, the cheap 20€ ones, which look so ridiculous :D Those help very well, too. Another trick: Especially when you sweat much you often get foggy lenses. Against that you may get so called Anti Fog Wipes for Glasses & Lenses . But just to be sure check before if the HMD uses normal glass lenses. If it doesn't better check in the manual of the device which types of chemicals you may use with them.