The cone and the clutch style were both oem GM. Never saw a cone type 12 bolt. Never saw a cone type Chevy 8.5 or 8.2. Some Pontiac/Olds were cone type w/8.5 rears. Both styles were considered 50% bias.
Auburn produced cone type as soon as they could. They sold a high bias (75%) cone type, but I have no experience with them.
I have used the Yukon 'Eaton" style and they work. I refuse to have an opinion about increasing the preload. If you need a spool, get one.