These palms are literally "bullet-proof." From what I have observed, these two palms are hardier than Lagerstroemia indica (Crape Myrtle). If you can grow a L. indica in your yard, you can definitely grow these two palms! BTW, I used *zero* protection. They were exposed to the elements. However, they were planted on the south side of my house, thus they were exposed to only z7a minimums this year (which is normal for me).
S. minor suffered minimal 10% leaf-burn; R. hystrix with +/- 5% leaf damage. One of my R. hystrix's (the most mature specimen) didn't suffer any damage and actually put on new growth during January and February! In some cases, S. minor can actually be hardier than R. hystrix because it's growth bud is deeper under ground, which is advantageous if you live in a climate such as mine!
I'm not telling you to insinuate by my report, that you can grow these palms in your zone 6 yard, but I can tell you it's definitely worth a shot! I doubt you would be disappointed! With all of that said, I purchased a Trachycarpus fortunei (5-gal.) back in November, where it spent the winter indoors. I finally planted my new Trachy on April, 16 in a nice rock bed next to my barberry bush. It will require protection during nights when temperatures drop below 10F, but I have reason to believe I can even grow this Chusan palm in my So. Illinois climate!
I recently purchased cold-hardy Nerium Oleanders (white, yellow, and pink), and plan to give this z8a evergreen a try! However, it's highly toxic, so I'm still deciding on where to put this beautiful blooming shrub! I planted Cannas, Elephant Ears, and a Ficus elastica (rubber tree) yesterday. The rubber tree is a zone 10a plant that I purchased from Lowes. I'm going to use it as an annual. Also, I purchased a new 4' 'Hamlin' Orange tree to keep on my patio.
My Dwarf Meyer Lemon is beginning to fruit and everything has "sprung" to life. Now I must plant some Musa sometime within the next couple of weeks and my yard should be good-to-go! That's all I can report for now.

Regards, Zach