what I think I may now be doing if looked at it from this perspective is hanging on for dear life to the Self and attempting to ignore or quieten the parts.
That would suggest that, in actual fact, a 'manager' is in control, not true Self. Managers are tenacious things and need to be gently prised out of the cockpit. :p I've got loads of managers who rotate control depending upon the situation. IFS says that if you feel anything other than compassion and curiosity, it's a part that's thinking/feeling, not Self.
Absolutely you shouldn't do EMDR without trust and stability/containment. We're doing this IFS stuff because I have massive trust and containment issues and am completely incapable of generating a 'safe place' in my mind.