Have you tried looking through the camera with the SFX filter in place? In bright light, especially with a fast lens, you will actually see something and it will look infra red, i.e. Wood effect of light foliage will be visible to the eye (I've tried it). Do you have a RF camera?
I haven't tried taping a filter to the film gate but it seems as if it should work if it can actually be doen without interfering with film location or shutter operation.
Re ISO only you can decide this because only you know what sort of negs you want (plus your camera may respond differently, we don't know what dev you're using etc etc, i.e. all the normal factors controlling film exposure and evelopment apply to HIE), I'd suggest bracketing the first roll and noting your exposures. A starting point would be the range I use for incident light metering with HIE: ISO 50 or 100. NOTE: this is for the film behind the lens & shutter set up only.
Thanks All !!!!!!!!
Some great advice.What about taping a piece of filter between the film rails,I've read about this before.Lets you focus without the hindrance of an opaque filter.If I did that what would I set my ISO to? The Ilford filter is marked B98.
Thanks