Punctuation typography

First some refugees from another thread:

And, by the way, in the top line of the iPhone screen, the colon in the time stamp on iPhoto (10:36 PM) should be changed to a period (10.36 PM), just like the times in good railroad timetables. Also AM and PM should be in lower case. So instead of 10:36 PM use 10.36 pm. These and similar typographic delicacies for time-stamps and timetables are discussed in Enivisioning Information, 104-105.
— Edward Tufte, January 11, 2007

“.” or “:”, using a 24-h clock must be superior to am/pm?
— Peter H (email), January 12, 2007

In re: ET’s inclination towards the “period” instead of a colon for time-stamps, I have begun to see (and use):

i) the “period” in phone numbers as well – 650.555.1212, and

ii) only a small “a” or “p” after time numerals – “….will meet you Tues. at Peet’s on campus, 7:15a.”

These seem tidy; any reason/s to think either confusing or unappealing?
— David J (email), January 20, 2007