We added some double thick bubble wrap insulation to our garage door this summer while working on the teardrop. It made a huge difference as the door is aluminum and gets full sun from the south all afternoon; to the tune of 10-15 degrees. Before we install the headliner I am curious if anyone has experience with the reflective barrier used on bubble wrap insulation without the bubble bulk.
Unfortunately for a radiant barrier foil to work it requires an air gap on the inside. If you put the liner directly over the top of the foil it would become a conductor of heat and not help at all. The bubble wrap part of the barrier you used on the garage acts as an additional air gap for the outer most layer of foil making it more effective.
If you want additional insulation you could line the backs of the CLC TD liner pieces with closed-cell elastomeric foam. 3/4″ of elastomeric foam has an R-value of about 3. The foam will also help absorb sound.