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Google's your friend when it comes to finding obscure model sources.
You know, I just took a look at my Nikon body and, similar to what you described, the F-bayonets are all different sizes (approx 22, 20, and 18mm). Also, the opening is about 46.6mm in diameter. A quick Google search tells me that your J1 camera has a similar pattern, but is about 4-8mm smaller in diameter. Maybe you could simply scale the macro adapter down to around 81.5% or 90% and see if that fits.
Also, you'll have to use a full manual lens with these since the J1 camera won't be able to open the aperture without an electrical connection to the lens.