Thanks for your post. Sounds like the winter prep is pretty good. I sometimes use double row covers with straw added as the weather gets colder. I grew a whole bunch of lettuce and greens that way one winter.
I also have painted milk jugs or soda bottles black, filled with water, and placed them around the edges of the planting bed. If a bed is placed close to rocks or blocks that are situated where the sun can hit them, that works too. The heat built up during the day helps keep the temp warmer at night.
What a unique idea. You-all amaze me here. It makes perfect sense and I have several blocks I’m not using that were in the back of my truck. I went over board a couple winters ago for blocks to give weight in the back of my pick up truck. It didn’t seem to have helped. Driving a truck takes some time on rain and snow. LOL Looks like I’ll be moving blocks.