Excellent write up. I did accentually the same thing only I used Permatex ULTRA GRAY silicone gasket maker. Really tough stuff and only needs to be applied once, but needs 12 hours to cure. I did this on my Ducati Elephant 900 more than ten years ago. I put 65,000 miles on that bike running the rear tire only tubeless. Now, with my KTM 950A, I'm on my second rear tire and at 4,500 miles on the front, both tubeless. I went ahead and did the front too on this bike because I almost never go off road and run 30psi in each. However, like you I do not recommend to anyone that they run the front tire on this bike tubeless because, as you pointed out, the front wheel is not a safty rim.
Again good write up, thanks.