What will you be using it for?

There are many different kinds of silicone that can be used to simulate skin.
If you are making prosthetics or anything that will come in contact with real skin,
you will definitely want to use a two or three part platinum cured silicone (cine-skin or xp-245)
that you can order from Burman Industries or Walco.
Keep in mind that the more of part C ( the softener) that you use, while it
makes it softer and more elastic, it will be stickier. That has been my experience at least.

Best bet, contact one of the companies that I mentioned and ask
for the manufacturers' contact info. Then call and talk directly to the chemist.
That is what I have done in the past.
Good luck to you!

Look into thermal-gel. It stretches and remains strong. It's not toxic... well... other than the fumes it puts off when you are melting it. It may be even too elastic for your purposes

Foam latex can make for very realistic movement and feel if made to the proper density. Unlike simple latex, it has a spongelike structure with adjustable cell sizes to achieve a number of different effects. I like a nice dense foam for real fleshiness.
Have you considered looking into either learning how to run foam, or possibly hiring someone to run foam for you?

Hit me up if you'd like more info.

I've been working recently with a latex-gelatin-latex layering process and I've been getting great realistic results.

The skin wrinkles like real, feels real, and it has amazing tear strength.

Is the skin for a prosthetic, or appliance? Silicone is pretty neat for appliances. Wolfe just came out with a new flesh that is eerie. Works good with medical adhesive.

Is this a one off cast, or cast from an UltraCal 2-piece cast, or cast from AeroMarine ? Will it have a skeleton or armature?

For a 2 piece cast of an articulated hand, I embed prepared fingernails into the release, paint pink pigmented silicone on the backs, tweeze hairs onto the top half of the cast with Cine-skin platinum silicone, seal the mold and float the casting with Cine-skin platinum silicone, starting with the bottom cast and fingers, Let it dry for a day. Bag and wrap the knuckles of your skeleton or armature with rubber bands just to hold the digits off of the first pour and accent the knuckles. Fill with a pigmented thin RTV or foam latex. Green RTV is zombieish, pink or tan is neutral. Pull the next day and dust with corn silk, and wipe clean with a dry cloth. Check fingernails for displacement and stray silicone. Manicure. When fingernails pop off, reattach with super glue, or spirit gum if you like the effect.

I'd like to hear more about Papa D's approach. How much can that ply stretch?