Hi Will
I understand the need of having different saved parameters for reports.
At this point what we recommend is a Read Only permission for all viewers and Read-Write permission to administrators, so they can save the most common filter options for everybody's use.
We do not recommend Execute Only for reports - this is a Read Only right without actually being able to see the resource in repository, search and library pages. It should only be used with datasources, resource bundles, images, etc - resources the user doesn't need to see but has to run them.
We also do not recommend Read-Write to be given to all users as this could lead to multiple report copies and duplicate information that will be hard to clean up.
This said, we currently have an enhancement raised with Jaspersoft to improve the saved parameters functionality, which is still being worked on.
I hope this helps -Nika