Pure beta maps will come from individual conditions (that is, those that go into a contrast). The effect size here would be analogous to the “con_XXX” maps from SPM.
Yes. You have beta maps for your individual conditions, contrast maps for the difference between the beta maps, t-maps for the statistical significance of the contrasts, and z-maps for a normalized version of the t-maps. Outputting the z-score will get you directly to the last step, which will likely be useful for the next step in your analyses.
I’m sorry I have the same problem. I need a second-level GLM analysis between groups. Do I understand correctly that I need to save contrast maps between selected events at the first GLM level in order to calculate the contrast between groups at the second GLM level?