Trace Events

I am looking to enable 2 specific events for memory checking on my 11G instances.

However, I would like some advice as to the actual syntax needed to enable event 10235 and 10501 (memory checking events) as I am somewhat confused in particular with the appropriate level to choose to start the tracing.

is this correct - "alter session set events '10235 trace name context forever, level 1'; "

are they other levels available and what additional information do they provide ?

Also, do I need to enable event 10046 first and how much data will I expect to capture in the user_dump_dest location ?