Ok, I'll play. Currently, Motrex 10-60 syn in the powerplant, and Redline shockproof light in the transmission and rear drive.
I ran the Centauro (similar architecture) 42K miles on Mobil 1 V twin and Mobil 1 75W/90 in the transmission and rear drive without issue.
Using synthetics, I change once a year or every 6K miles. Filter once a year.
If a guy is willing to change more often, I'm sure that any quality SG rated dino oil from around 20-50 would be fine.
Why Shockproof light? Many if not most run heavy. Heavy is so tenacious that if you follow a regimen of drain and measure, quite a bit of Heavy will stick to the gears and you will overfill (especially) the rear drive. BTDT.
That's my story, and I'm sticking to it..