diacriticals

[Jinavamsa at aol.com]

I understand that Sanskrit long vowels are doubled (replacing the macron or
older circumflex accent) and that consonantal diacriticals include a
preceding period for the retroflex (cerebral):
 .r .r .th .d .dh .n .m .s
and similarly for visarga .h
that palatals include ~n and "s
What about representing the overdots of 
the gutteral n 
the anusvaara (both the dot over the m and the dot resting inside a little
half-circle cupping the dot from below)? am I forgetting any other  relevant
instances here?
thank you.
Jinavamsa