For CLO ratings associated with synthetic insulation, the following formula is how it's calculated: 84 - (CLO rating * mass of insulation in oz/sq yd * 14). This assumes no base layer. If you're going to wear a base layer to bed, the equation changes to 70 - (CLO rating * mass of insulation * 14). The result is in degrees F, and it assumes perfect fit, no humidity issues, no wind, and the theoretical "average" sleeper.
I'm going to assume your daughter and you are going to wear something to bed (most folks do). So, the rating for a 2.5 oz/sq yd Climashield APEX quilt would be: 70 - (0.82 * 2.5 * 14) = 70 - (2.05 * 14) = 70 - 28.7 = 41.3* F. (I pulled the CLO rating from the Thru-Hiker website.)
So, roughly 41 F would be the rating assuming perfect conditions. I'd eyeball that as a ~45* F rating for most folks' comfort while sleeping, since perfect conditions don't usually exist outside of a lab. Me, I'd be willing to push that down to freezing-ish, but I'm a nearly-inhumanly warm sleeper.
Hope it helps!