I knew this once, but...

When entering the parameters for the Set Variable script step, what is the keyboard shortcut to access the Specify... button? Tab moves from input field to input field, but does not let me get to the buttons.

When I type "Set Va"  and Set Variable pops up, I hit 'Enter' then space bar on PC

you can save yourself many keystrokes: "sv" will do the same.  Hint: first character of each word in the script step works really well.

gtrr for Go To Related Record, sf for Set field, scd for show custom dialog,...

I'm sorry, I didn't make myself clear.

Thanks for your feedback, but your suggestions apply before my real question.

I want to activate the Specify... button (#2 in the screenshot) and enter the Specify Calculation dialog directly after entering the variable name (#1).  Or, having pressed the Tab key, and focusing on the Value field, go from there to the Specify Calculation dialog.

Either way, directly from the keyboard.

I've asked this too. We've started to use Insert Calculated Result a bit more.

On Windows the tab key cycles from the "Name" field to the "Value" field and then to the "Specify" button. Then "Repetition" field, "Specify" button, "OK" button and "Cancel" button.

In some cases, when there are multiple buttons that the tab key should cycle through after on another, I've found that the cursor keys will let me select different buttons.

As you're on Mac, it must be different?

Yeah, tab cycles through the three fields (Name, Value, and Repetition). Option-Tab will switch from  Cancel to OK (once, never cycling back, and inserting an ASCII Tab character in whatever field is in focus.).

Nothing else does anything in the dialog.