You can choose to throw your faith in with the silicone items from "Real Gaskets". Then you get to be sorry and do it over again with the cork ones that belong there; see here.

I glue the cork gasket to the pan with ultra black or ultra grey, put upside down on floor (plastic wrap so it doesn't stick) stick some weight on pan and let dry overnight......

If silicone is a bad option, what other option do you suggest other than cork?

how do you keep it from sliding out of place?

Tie loops of sewing thread through each bolt hole in the pan + gasket.

Also, if you choose to use a gasket "sealer" (goop of some kind), use one that isn't going to serve as a slip-'n'-slide lubricant during the install. Hang the pan gaskets from the garage ceiling (fishing line) and use this stuff, then walk away from the gaskets for an hour or more so the stuff is completely dry and tacky rather than slippery before you go installing.

Charlie, I always glue the gasket directly to the block with a very light smear of black or gray silicone. I also put fairly large dabs on all the corners where the gaskets and seals meet. I also have some studs I made that hold the gaskets in place and guide the pan down.