Welcome Newguy!!!

Sorry, I can't help you with the mirror. I have a couple of the starflash types, but the only times I have ever used a mirror for real (to lead a chopper to my location), it was with a plain old two sided thin metal "camping" mirror with a sighting hole drilled in the middle of it.

As for the whistle, the one I carry daily, on a dog tag chain, is the ACR . Flat, pretty loud, and I always have it. Works for me...