It became necessary to adjust the float level of my sons stock 1200 coupe today, so it was out with the workshop manual, the tools, & the carb top.
The book says that when the carb top is inverted, the top of the float should be 12mm from the gasket face of the carb top.

This is usually done with a 12mm drill by rolling the shaft across the gasket face & under the float, but i didn't have one. A quick glance around & i reached for my micrometer & adjusted it to .472 inch [12mm, it was an old mike.] I grabed the 1200's factory jack handle & discovered that it was exactly 12mm in diameter, so i was able to complete the job.
Those clever Datsun engineers are thinking all the time.

Another tip?
The pointy end of the wheel brace, the part used for prizing off the hubcap, is small enough to use as a screwdriver for that emergency "adjust the points by eyeball on the side of the road" job. I learned that trick about 20 years ago, so keep your original toolkit intact, you never know what you might need it for.