Re: suppressors good flash hider
I would not be at all surprised if a sound suppressor hid flash better than one of the best flash hiders (Be Meyers or Vortex) on a .308 after the first round.
It's going to depend on the make/ model. The higher performers (assuming no titanium blast baffle) will probably hide flash best.
If you want to increase the flash reduction with a suppressor, putting a teaspoon of water in the blast chamber and shaking it to coat the walls will probably beat any flash hider around.