How to determine the optimal stimulus sequence for a slow event-related fMRI experiment?

Hi all,

In my experiment, there are six conditions belong to two independent variables (2x3). We are interested into the interaction effect of 2x3 ANOVA on activation (beta values) of six conditions.

A slow event design will be used: each event lasts two seconds, with intervals between events ranging from 8 to 14 seconds. Each session comprises 32 events.

Are there any tools or MATLAB codes available to help determine the best stimulus sequence for this slow event design?

Thank you!