I did not. I was asked to travel about inspecting installations prior to first flight, or to assist with installations.
But if asked I would have suggested Ceramic seals.
We raced with Carbon seals and later, Ceramic seals. Carbons wear too fast for aircraft use but are soft and leave the housing chrome looking better than new as the years go by. No detectable wear at all. Near perfect sealing. No skipping, no need for an extra spring.
Same for Ceramics. Light weight. No wear. Very expensive. But if you can use the same housings for 4 or 5 years, then not so bad. The duty cycle of an aircraft engine is much tougher than that of a racer or street engine.
All early engines Had the wide carbon seals. We machined them down to fit the later rotors. So early housings would often run well over 100,000 miles. The iron seals with a chrome face have you running a chrome face against a chrome housing. Bad Mojo. With Premixing and or oil injection not so bad. Hard starting suggests
worn apex seals. Both ceramic and carbon seals need to be sized to the housing width.
Any question, any time.
Lynn E. Hanover