I'm not sure that squawking 7700 is the best solution. You would certainly get the undivided attention of the controller concerned and any turns, climb or descent that you wanted but at the expense of every other aircraft in the sector.
An emergency does not have to be declared for ATC to use emergency separation but is 500' enough in bumpy air? Me, I'd rather aim for a couple of miles of lateral separation than rely on 500'.
Max
It seems you did the best you could and I have no doubt that your actions were appropriate to the situation. I just have to stress that there may well be several other pilots thinking along exactly the same lines as you and all inevitably aiming for the same bit of sky.