Yes, the /i switch is for case insensitive matches.
"X to Y occurances", is: {X
,Y}
Note that while you can use a regex containing commas in commands like /filter directly, for $regex() you have to store the regular expression first in a variable or the like, because the comma char is part of the $regex syntax itself. For example:
var %reg = /-[A-Z]{2,3}-/i
if ($regex(sometext,%reg)) { do stuff }
