Q:

ASP.Net MVC - Data Design - Single Wide Record versus Many small record retrievals

I am designing a Web application that we estimate may have about 1500 unique users per hour.   (We have no stats for concurrent users.).   I am using ASP.NET MVC3 with an Oracle 11g backend and all retrieval will be through packaged stored procedures, not inline SQL.   The application is read-only. 
Table A has about 4 million records in it. 
Table B has about 4.5 million records. 
Table C has less than 200,000 records. 
There are two other tiny lookup tables that are also linked to table A.
Tables B and C both have a 1 to 1 relationship to Table A - Tables A and B are required, C is not.  Tables B and C contain many string columns (some up to 256 characters). 
A search will always return 0, 1, or 2 records from Table A, with its mate in table b and any related data in C and the lookup tables. 
My data access process would create a connection and command, execute the query, return a reader, load the appropriate object from that reader, close the connection, and dispose. 
My question is this....
Is it better (as performance goes) to return a single, wide record set all at once (using only one connection) or is it better to query one table right after the other (using one connection for each query), returning narrower records and joining them in the code? 
EDIT:
Clarification - I will always need all the data I would bring over in either option.   Both options will eventually result in the same amount of data displayed on the screen as was brought from the DB.   But one would have a single connection getting all at once (but wider, so maybe slower?)  and the other would have multiple connections, one right after the other, getting smaller amounts at a time.   I don't know if the impact of the number of connections would influence the decision here. 
Also - I have the freedom to denormalize the table design, if I decide it's appropriate. 

A:

You only ever want to pull as much data as you need.  Whichever way moves less from the database over to your code is the way you want to go.  I would pick your second suggestion. 
-Edit-
Since you need to pull all of the records regardless, you will only want to establish a connection once.  Since you're getting the same amount of data either way, you should try to save as much memory as possible by keeping the number of connections down.