It is possible to adjust the parameters of each Effect Layer as follows:
Select the Effect Layer you want to adjust.

In the bottom part of the window, you will find the settings and parameters of the Effects layers.
Size, allows you to adjust the effect size of each individual layer of the Effects Group.
Offset, allows you to set the Phase start of each layer individually. This allows you to set different Effect Layers to start at different times within the same Effect Group.