Several years ago, without much for a guide, I cured and cold smoked at temps around 100F until I liked the color of the slab.
Taking the internal to a safe, basically cooked temp, pretty much insures a safe product, cooked or even uncooked. Home curing is not an exact science.
I've not noticed much of a difference in quality between all cold smoking and bringing it up to 140-150.
I still cold smoke until it's close to the color I want, then bump up the temp to finish it at 140-150.