I still prefer the old-fashioned mole skin that was used to cushion corns and bunions. I am talking about the Doctor Scholes' sheet variety.
Properly used. mole skin only adds height to the comb but not thickness. The same cannot be said for many other "comb raiser thingys".
I have learned that stocks' combs should be waxed before mole skin or other adhesive-backed comb raisers are applied. The wax serves to prevent damage to the stocks' finishes.
Of course, other means of adjusting comb height are available, too. For example,I have a denture-wearing friend who takes out his upper plate for 16-yard targets and replaces the plate when he shoots handicap. Thus, he does not need an adjustable comb because he already has an adjustable face!
