Both of the followings work:
command! mCo bash mCo.sh %f:p %s; read -n1 command! mCo bash mCo.sh %f:p; read -n1 %s
Where is the right place to put the %s, %v, or %i macros?
%s
%v
%i
Anywhere. Position doesn't matter as shell command isn't parsed except for %-sequences.