We've discussed this topic in the past and like many such discussions there are a range of opinions. Some posters like illumination with NV clipons, others have reported they've never used it.
With thermal clipons, I think there were more users reporting they used it.
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For me, in six years of going out at night with thermal and NV clipons ... I have said I used illumination with NV clipon exactly once. And that was target shooting in the shadows with no illumination. In general, I find the green tube NV to not require any illumination. I would be fine getting a non-illum T-3 to use with an NV clipon.
For Thermal clipons, due to the black/white nature of the image, it is possible the black of the reticle might "fade" into the black of the image. Adding magnification might help, if there is time. Inverting also might help.
So in theory, I like the ability to have illumination to use with a thermal clipon. That said, I have never used it when hunting. Also, regarding the T3, I am a fan of the T3 and have two T3 scopes, but I don't think it is a perfect reticle for hunting. But I will be trying it this winter and will be posting about the experiences. The T3 illimunation is also not of much use in general, nor behind a thermal clipon. Worst case, I might have to invert, that can be done, but I've never done that with a critter in sight.
Now illumination in the day can be useful when hunting and that's mostly where I use illumination. But then also at short distances on low magnification a tiny bright dot is "perfect" illumination in my book. So again, the T3 illumination itself seems to be mostly designed to help you find the holds when shooting longer distances ... and that just doesn't line up with hunting for me.
