How to serialize and deserialize Django ORM query (not queryset)?
You could create a new model user_option and store the selections in this table. 
From your question, it's hard to determine whether it is a better solution, but it would make your user's choices more explicit in your data structure.
My use case is that I need to store queries in DB and retrieve them from time to time and evaluate. Thats needed for mailing-app where every user can subscribe to a web-site content selected by individually customized query.
Most basic solution is to store raw SQL and use it with RawQuerySet. But I wonder is there better solutions?