Going from pre-70s V Reg to the newer post-70s V Reg Squareback

Not sure what you did, but seems to work. With the 1970's Vreq (triangle plug), at the ALT connect +12 V switched power to one field terminal (that can be from your new relay), the other (low-side) field terminal goes to the Vreg "fld" terminal (grn). That is termed "low-side control". On the Vreg, the blue wire goes to the +12 V you want to regulate (usually IGN from cabin, but the output of your new relay is better since closer to BATT+ value).