Dear Karina,
setting up a single model that would give answers to all questions only works for really simple designs. In your case, you should have a look at the preprint mentioned here https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=spm;6b4aa282.1806 by Martyn McFarquhar. In addition to the fact that you would need 5 factors and SPM only allows 4 (this limitation is hardcoded in many places throughout SPM stats code), the manuscript explains nicely some of the reasons why one needs separate models for answering different types of questions about the data. As a general rule of thumb, for each question to your data you should try hard to only bring one contrast per subject to the group level. If this is not possible, still try to keep your 2nd-level models as simple as possible.
Hope this helps
Volkmar
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