Complicated data capture and management

Going to try to launch an event that will target 200,000 registration entries (data records) that will each have a max of 36 fields.

The data is planned to be entered from a user web page form on a Word Press site. Looking at Gravity Forms but they offer extremely limited data management capability so wondering what other options may exist.

Here are the queries that must be performed:
1. Subtract field A from field B in each record and post the difference in field C.
2. Compare the field C results for all the records and creare a table with the lowest C value record and matches.
3. Query the C value matches for field D and create a table with the lowest D value record and matches.
4. Query the D value matches for field E and create a table with the lowest E value record and matches.
5. Repeat until there is only one lowest field value record with no matches.

I haven’t a clue where to begin or what to do in this ambitious project and I am more of a content person than a technical person.

Thank you for any advice you may be able to offer.