missing the piont ?
It would seem to me that all this talk of IMC ratings vs FAA/IR is rather off topic.
The time for declaring an emergency is when you think that it will help the situation , if the guy on the other end of the radio cant be of asistance then the chances are that the extra workload of the emergency radio procedures will be of more hiderance than help.
Once you have contained the situation then it may be time for a "mayday" call , I am left to wonder how meny forced landings have ended if disaster because the low time pilot was trying to talk on the radio rather than watching the airspeed and the field he was trying to put the aircraft into.
The emergency call is a good way of getting you the priority that your situation requires.
I once had a landing gear problem going into a large london airport , the drill on the aircraft was NOT to cycle the gear , this limmited the diverson options to an even larger london airport.
As I was going round the hold trying to sort this problem out I get a call from ATC to say that the airport manager had been on the phone and asked us "not to land at his airport" ( probably woried about the effect of a blocked runway on his duty free sales ) The ATC controlled reminded me that if I declaring an emergency would take the airport manager out of the loop , so that is just what I did.
Fortunatly the nose wheel locked as it touched the ground !.
I have to say that it was my veiw that the extra pressure that was put on me by the airport manager was not helpfull and I should have raised an MOR about that alone but the ATC attitude of "declare an emergency and get this idiot out of the loop" was most helpfull !.