I've never protected trachys that big so my method of protection wont work for anything that size. If you keep them in the garage over the winter, keep them out when nights are above 25F-30F (depending on duration) and during any snow/ice events. The more time it spends outside over the winter the better so you don't have to worry about it readjusting to the outdoor sun.

Good luck!
-Alex

Thanks for the reply Alex. Was there any damage to the fronds after winter.
Thanks,
Joe