It is interesting to me that you want to use larger and larger crochet hooks for your amigurumi. For me, much of the cute of ami is in the diminutive size and close, even stitches of single crochet.
I prefer hook C or D with worsted weight yarn.
I have also used crochet cotton to achieve smaller amigurumi.
In my research, 10" is the max size for amigurumi.
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