I want to allow users to enter a set of data that will be represented
by a number of rows in a single table.

Should I use an ActiveRecord descendant that does not actually connect
to a table (overriding all the methods that would complain about that
and creating mutators and accessors for all the virtual fields) ?

Or should I use lots of facade columns in the real table's Active
Record and create more instances inside the overriden Save method ?

Cheers