How to increase max size of sqlnet traces?

We have an annoying issue whereby a connection fails with ora-3113 after retrieving several million rows. I am trying to use sqlnet tracing to learn more about the issue, but the server-side trace caps out at 4gb (trace_level_server=16). Is it possible to increase the maximum size of the server-side trace? If so, how? I also tried trace_level_server=10, but then I realized that the auth_sesskey is not captured (or at least, I could not find it), which makes it rather difficult to match the thousands of server traces with the client trace.

Help? :)