Unfortunately the advanced search filter is reset for each individual search. There is no method to keep these search filter settings permanent.

Maybe one day LW will add an option to keep identical search filter settings in the same way you can set your default search type to Audio or video, etc. One possible downside to keeping these settings might be that if the person accidentally sets their search filters settings too high & then they will find much more limited search results showing & may get confused about this. (example: file size set to 100 MB for audio search.)