For ranking top guys I think it makes far more sense to go with Tiers than specific numbers.
That said, Tatum was All-NBA last year, meaning approximately top 15, and I don't see any reason to not include him in that top echelon again for this season.
Granted, Durant and Curry are back now, which may crowd out some All-NBA spots. But it remains to be seen if Durant is still an All-NBA caliber player. I suspect he will be very good offensively if a step slower, and significantly worse defensively.