Robrob. Unfortunately I’ve thrown away my old T67A POH copy but I don’t remember it mentioned anything other than the standard full opposite rudder/move stick forward technique. Because of the long wings, I suspect that inadvertent outspin aileron might have have been another factor in delayed spin recovery.
The T67A was a nice aircraft for gentle aerobatics but it was frightenly easy to operate it outside the rear Cof G limits and I suspect that they often were. The low max AUW meant that the fuel load had to be limited for Aeros two up. As the fuel tank is forward of the cockpit this moved the cg aft. The cockpit seats were on rails so two 170 lb people with long legs really shifted the C of G back. In the end it was necessary to have a complex table of fuel load/ crew weights/ seat positions for the group members (not highlighted in the POH). The result was that I ( 190 lbs long legs) could fly with my wife (small light person) but nobody else in the group.