I used to have a pair of toy IR goggles (Eyeclops brand) which worked great after I upgraded the lens. It had two banks of IR led lights, one which would glow red (I cut these out) and one which would not. I never had any problems fogging film with the non-glowing leds. Unfortunately, not knowing much about electronics, my snipping the cable on the glowing leds lead to the failure of the light sensor, as there was a switch that allowed you to choose between the two light sources. I would go outside with the goggles on, turn the light off (thus switching to the now non-existent glowing leds, inadvertently sending extra power to the sensor, slowly killing it), place a IR filter in front of the lens, and get to see what my IR exposure would look like! Note: I never did use the goggles with IR film, you can get IR leds that only produce light at higher wavelengths than IR film can record, but my goggles began life as a toy, so technical info was very much lacking.
To answer your question then, according to Ilford, SFX has sensitivity up to 740nm, which is just about the limit of the visual spectrum, so I would hazard a guess that if you turned on your goggles in a dark room, let your eyes adjust, and then look right into the IR light on the goggles, if you can see the light chances are the SFX will too. If you can't, then it shouldn't be a problem. In either case, good luck and I hope you obtain great results!
