Another vote for big/big method that snotty mentioned last page, specifically:
The correct way is big/big not through the derailleur plus a pair of links on top of the shortest you could make it, from there you usually add another pair for 1x and another for suspension.
I worked with a very skilled race mechanic who told me this was the standard Shimano method. Also happens to be the Sheldon Brown method IIRC.
Yup Shimano and the right way to do it 99% of the time.
I've found if you're a little slack in small/small and the big/big sizing is ~5mm off letting you take out a link then it's usually fine too.
Another vote for big/big method that snotty mentioned last page, specifically:
I worked with a very skilled race mechanic who told me this was the standard Shimano method. Also happens to be the Sheldon Brown method IIRC.