So the results are in!
Temp when I turned on the heater around 6pm was 55.
Low tonight is supposed to be 41.
I shut off the heater right at 9pm. It had just flipped to 61 when I did that. So I got 5 degrees in around 3 hours.
I looked at the temp at 9:30 and it showed 60.
Temp when I looked this morning at around 8am - 59
So I turned on the heater (8am) and less than 1/2 hour later it was again at 61.
So I have to conclude that I lost almost no heat last night. The drop in temp from "just" 61 to 59 was most likely a circulation related drop. So as soon as the pool was cranked back up to full speed, the heat went back to 61.
I am very pleased with these results and will keep my heater on all day!
Also I think this will not be a problem to remove by myself. I put it on by myself before it was even cut. I got the 8 mil plastic so the entire cover could be carried by one person. I'd say it was maybe 30-40lbs at the most (dry).
We'll see when I take it off but my plan was to just fold it as I remove it and stuff it in a deck box and not use the reel. I'll see how that goes.
This is the one I got btw in 25' x 45'. I ordered Wed and got it Sat.
https://www.amazon.com/gp/product/B01N9Y2DYJ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1