Okay, at 27c room temp heat becomes an issue. I have cut back the felt to allow 1-2mm gap around the face. Also noticed that if I peel back the bottom shades completely light is being reflected off my cheekbones, with very little light coming in from the top if I remove the top shades. But if I pull back the top covers heat is released without too much detriment to reflections.
Also, with the reduced reflections from the rear/face the ones coming from the front bezels have become very noticable. However, I cut a front felt surround that sits over the frame which does a very good job of eliminating reflections (totally. Only leaving the ones from my prescription glasses - which will get the treatment shortly I imagine). However, it does have to extend well past (into) the frame in order to stop light getting in. Nevertheless, it does not encroach into my screen field of view.
In fact, I'd say the Bat Vision accessory actually enhances viewing (compared with no 3D glasses) as it also blocks out a great deal of annoying periphery junk (e.g. light fittings, pictures etc.), thus increasing the cognitive capture of the screen ("immersion" I suppose they would call it).
As an observation, what a silly finish (gloss) to an otherwise great set of glasses - it really detracts from their performance. If there's another pair of RF glasses with a matt / rubberised finish then I would recommend buying those. Anyone know of any?