I just got a Hennesey "Cub" for my son (age 9) and want to get him out in it ASAP but I'm torn on what to use for bottom insulation. I dont have the funds to purchase a "summer" UQ and I'm not sure if a pad is going to work with all of his flopping around. I could try to make an UQ out of an old sleeping bag but I fear that I will just end up wasting my time making a mess of it and not having it fit properly. So what do you folks with kids use for bottom insulation?????