If you use tartlet pans like mine, you can press down the cookie crust with the back of a teaspoon initially, but you’ll have to use your fingers to press it against the sides. For small ramekins, the teaspoon will work on the sides.
My tartlet shells are about 3 1/4 inches wide on the bottom and the sides are 3/4 inches tall. the filling with three tablespoons removed for the decorations just filled them to the tops.
To remove the tartlets from the pans, slip a knife around the sides before lifting the bottom (still containing the tartlet) and letting the ring slide off. Then slide the knife between the tartlet bottom and the crust before slipping the bottom off the crust.