Setting up the correct tables and relationships need to be the first step, then you can figure out from there what options to use for designing the user interface to enter, edit and view the data stored in those tables.
To help you do that, we need to know more about what you are trying to do.
I sounds like you are selling something (advertising?)
Most sales systems are built around the following tables and relationships:
The Products/Services is the table you use to keep track of the items and/or services you offer to your customers. Invoices represents a single sales transaction. And LineItems is used to list the individual goods and services purchased/rented on a given invoice.
It sounds like your "unchanging list" would be a list of records from the Products/Services table. The specific services selected for your customer (the yes/no and position fields) would be stored in lineItems. This is the table and relationship structure you'll find in the invoices starter solution that comes with FileMaker and also in this much simpler demo file created by Comment: http://fmforums.com/forum/showpost.php?post/309136/
While this is usually implemented with a portal to lineitems and a drop down list of products/services, it is also possible, with scripting, to set up a list of items from the Products/Services table in a portal that you can click to select them for a given invoice. The script then creates a record in LineItems when you click a row in the portal.
Thus, while "700 records" is actually a very small number of records (not unheard of to have over a million records in a lineitems table), the lineitems table would only list the actual goods or services selected for that invoice rather than a copy of every item offerred.