The dash can remember the settings for filtered results for the entire session, but not beyond that. Once the profile is logged out and back in the results would reset to their original settings; displaying all the results without filtering. How can I make the results filtering more permanent? IE: How to make the photo lens for instance always show photos from "This Computer" and not from Picasa or Facebook across sessions and not just temporarily?
I do not think you can. These seems to be stored in memory only and lost every time the service is restarted.
You could however uninstall scopes that you do not want to use. You could also disable "remote" scopes by going to system settings, privacy, and turning off "Include Online Search Results".
Failing that, you could always remove the .service files from /usr/share/dbus-1/services/
I STRONGLY recommend AGAINST doing that, but it is an option.
You can also file a feature request with the lense/scope maintainer.
I believe the ability to save previous seach results and filters would be done at the lense/scope level and not at a unity level. Though they may not be true.
TL;DR; You can't as of today.