Shim size for AM cams

[Project D]

First, 1NZ buckets are NOT shim under, but shimless -> you have to order the correct size for each valve.
The only thing you need to go standard to 1NZ buckets are ... the buckets. Nothing else change !
As to how do you find the proper size ? the same way than with any other setup-> you measure
But instead of measuring only the shims you have to take the buckets them-self into account. (A good micrometer is recommended at that stage)

As for the cam size, past 9mm of lift brands like Toda recommend to go shim under (or shimless)
But there are no rules set in stone. I have seen peoples run high lift cams with the standard shim over bucket.
As long as the profile (duration / ramps) is not crazy it might not cause any problems.
(Personally I would not risk it...)