The location of the default fixation mark cannot be changed, it is fixed to the display centre (this may change in the future). The work-around you suggested is indeed the recommended solution, and this fixation "stimulus" would be then more customizable: its size, position, shape can be anything.
A few tips:
- make sure you set your fixation "stimulus" as the last one in your stimuli hierarchy, so it always appears in front of all other stimuli,
- if you want to maintain this fixation "stimulus" during the inter-trial interval, check the "Keep as fixation" box under the "Onset" tab of the stimulus control settings as illustrated below:
- to prevent your fixation to interfere with the other default fixation marks, set the default ones with an "empty" or white space character in the Control Settings of the Experiment Properties:
Hope this helps!
-- The Psykinematix Support Team