A big advantage for me, less obvious, is that when sorting files or selecting a file for editing I need only take note of the last two characters of its filename. There's less chance of misreading or misremembering HM say than 091356.
Interesting, Robert.
But to be fair for the numbers, I think, you should compare
HM not with 091356, but with 356.
Because you would to have use only a 3-digit-number at the end, to achieve more uniqe files, as with your letter-system (999 versus over 600).
I speak often with clients, what photos must be choosen, and from my experience, a 3-digit-number-system (hey, is 481 better than 283?) is not problems for people to communicate, even a 4-digit-number is ok, but not more that good is a 5-digit-system
Unfortunately I do not know, how we can solve your unique system. I would like to help, but I simply do not know, how.
I wonder, if this is possible, I have no clue.
Hope, you get some hints for solving your problem.