There are no "best settings." Please understand that every setup, for every use case, will be very different. Any guides or videos that claim otherwise are misinforming. Your best option is to start with a base and adjust as necessary. Test, test, and test again. We are happy to offer suggestions for any issues you may be having, but we will not give you a list of settings.
EDIT: That said, it's highly unlikely OBS will function at any kind of watchable quality on that PC. You need a new one, that one is far too weak.
