It is so hard to tell. There is so many good ones out there.
I have seen my yucca brevifolias take -14F, the larger form burned more then the dwarf form did, but bolth survived. I think they are the hardiest of the trunking yuccas in my yard. They are not always hardy when they are young, but do better with age. I also see very good results from y. recurvifolia, and y. gloriosa. Y. elata is very hardy but will burn back to the ground in very cold weather when young but will grow back, as they get older they become very hardy.
There was others I recommended for different areas, but overall I think most of the common cold hardy trunking yuccas are showing good results

There is some that are not doing as good as others like- y. torry and y. riggida and a couple of others.
Sorry I don't have any seeds off my trunking yuccas yet, but have seeds off my y. neomexicania, and yucca gluaca.