I, personally, am in the ‘it’s counter productive enough to not be worth it’ camp. Once covered your daily loss will be next to nothing. 1/2 FC a day maybe (assuming no algae

). So that would ‘buy’ you 48 days in theory until it’s gone and we will be plenty cold by then. Then your mission is to open it before the water warms up to 60.
If you really REALLY want to sleep like a baby about it, plan to test and add in Dec before it freezes. You can pop 6 ft of the shallow end in a matter of minutes and reSLAM it. Brush it around good as it’s heavier than water and you don’t want it puddling. (Also be aware of where you brush it to…. You don’t want half a puddle there either). But in a matter of an hour you will be covered for the rest of the winter just in case.