session_cached_cursors and shared

I received a recommendation to increase session_cached_cursors parameter.

I'm having 11.2.0.4. We are using memory_target=8GB

Increasing this parameter will cause shared_pool to increase. Questions:

1) Since we are using memory_target we cannot increase shared_pool. Will the shared_pool increase by Oracle in this case?

2) What would be optimal value? I did not get this recommendation. Our open_cursors is 1024. Do we need to increase it that much?

Thanks