Hola Gorge,
I saw from the members map you are southern then me. My lowest temperatures in winter are -6ºC but only a couple of nights. Now we have -2ºC but temperatures below 0ªC are usually only a few weeks during winter.
I keep my big plants with no protection and i let the death leaves cover the stem and help to protect it. The smaller one are protected with a cylinder made on plastic net and filled with straw
This work yo me for most of the so called cold-hardy bananas (basjoo, sikkimensis, nagensium, chesmanii, yunnanensis) This winter will be the first for some other species (rubinea, maclayii, basjo 'rubra', itinerans, E. glaucum)
I will post some pictures later this winter.
I hope this helps
Conrad