As far as I am aware, There is no default option for the actual results.
You can have a default of what type of analysis takes place (as determined by the Parameters 1023-1026 in SPRO), but the actual output does not seem to have a defaulting option.
Only thing a user can do is set up a variant for their ad-hoc risk analysis and select the type of report format they wish to view as default. This may mean setting up a variant for each of your individual end users.
I do not thing user variants are used in the risk analysis embedded within Access Request.
Maybe worth raising the idea to SAP via the IdeaPlace website.