Are "ins", "hrs", "mins" and "secs" the technically correct plural abbreviations for "inches", "hours", "minutes" and "seconds"? I'm hoping that all examples below could possibly be correct.
Examples:
Plural: He finished the race in 4hrs 34mins 9secs.
Singular: His 4hr 34min 9sec finish was unprecedented.
Plural of 'inches': Garry was 5ft 10ins tall.
Singular of 'inches': Garry was a 5ft 10in man.