Is it a toy as in model heli or toy as in big boys and a real one?
The 28 vs 50 sec is a measure of viscosity so 50 sec would be thick and gloopy compared to 28 sec.
The short answer is that you can run a turbine on all sorts of fuel but what it does to the engine can range from sooting it up, corroding it, leaving gummy deposits, failing to lubricate key parts of the fuel control system, burning too hot etc etc. Put in the best fuel you can would seem to be a sensible dogma, especially if your life is going to depend on that engine running well.
PS, just seen from another thread that you have bought a well looked after EC120 - put Jet A-1 in it, if you can afford a 120 you can afford proper fuel
