Anyway just to side track, you don't need to consider buying a 77mm CPL much anyway. Later on in the hobby when you pick up a nice pro zoom lens, it will be 77mm threads, so it's much easier to just get a 77mm CPL, ND filters, GND and step up all your other lens to it. And as an additional bonus, Sigma 50 f/1.4 is 77mm too.
And u will get rather bad vignietting with a B+W gnd filter at 11mm on the 116. 12mm onwards is ok.
There are certain situations in which CPL could be used on a UWA but it's very situational based. Usually a CPL on a UWA leads to some "interesting" effects.