I assume you have the chain box set (for at least it's inclusion of the BN era rarities) so let us know what you particularly like of the NON BN era stuff on that box and then we can better suggest some stuff for ya (just an idea I had which I thought might make it easier to see where your tastes lay regarding "pre '75 Mac") and therefore hopefully help determine what specifically you might like from the pre BN days.
John