I recently ran into a blog that dealt with the CBN issue. The woman there said that, if she was making sleep meds, she decarbed for 4 times what the same bud and temperature would need for THC. I tried it the last time round when I made my current batch of MCT tincture. It seems to have worked well.
I use a decarb/infusion device that I made. An Inkbird PID controls the temp. It is a repurposed large stainless steel pressure cooker. No smell, large capacity, and I can program the inkbird for any temperature I want to use for decarb or infusion. Capacity is huge, but I don't tend to use it. When I decarb, I do the rosin, not the bud, and the rosin is in silicone loaf or muffin pans for the process. The thing can also be used as a still, to, for totally hypothetical example, produce 95% ETOH from hand sanitizer. But that would be illegal.