Gathering information to tune oracle row prefetching
This is an interesting question and differs significantly from the approach I have used.  The kind of information you are looking for would not be of much interest to me.  I would be more concerned with the number of rows displayed (or processed) for each query.  The place to capture that is likely in your application(s).

You may be able to gather most of what you are looking by enabling auditing for your queries and analyzing the audit data.

For batch retrieval which will use the full result set, I generally set a relatively large pre-fetch value (100 or so).  Tuning might be of value in some cases, but I would limit it to frequently run queries with large result sets where database fetch is a significant portion of the overhead.

For interactive applications I usually tune prefetch limits towards the number of items displayed on a page.  There isn't much value in prefetching data for the next page unless the users actually page to it.  It has been my experience, that users don't page down that often.  Anything past the second page would be overkill for the initial prefetch.

EDIT: Based on your comment, setting prefetch size to one or two screens of data may decrease latency on the link.  Fetching unused data will increase the load on the link.  Setting the link to prefetch data should also reduce the load on the link.