I think before trying to combat shrinkage, you should try to work with your properties (use the link by Kathymack). I sometimes use the diffuser, but you still shouldn't use it extremely often. I agree with Kathymack, you should learn to love your curls- shrinkage or not.
High Porosity, Fine, Low Density, Low Elasticity
Suave, V05, ACV rinses, CO, and Gelatine PT.
Curls