You can change the format of the strings by simple string coding:
(yes, all you need is a string)
Code:
PANEL* your_pan =
{
//Your stufff here
//Example digits:
digits(0,0,digit_format,NULL,1,variable);
}

STRING* digit_format = "%.0f";//Let's put it first this way
function change_digits(PANEL*panel,STRING* new_digits)
{
//Just a check if your panel is valid
if(panel == NULL)
{
return 0
}
str_cpy(digit_format,"");//Clear existing format
str_cpy(digit_format,new_digits);//And add new format to the string
return 1;

}


That's basicly how you can do it, when you add more complexity (ie need some text before format and so on) look for more str commands in the manual.