Your advice sought - slate tile on wall

[Mac]

The woodstove is a focal point of our living room, and we considered using cultured stone on the walls behind it. We discovered slate tiles were less expensive and look nicer (in our opinion). One wall is exterior, 2x6,16"on center; the other is 2x4, 24" on center. The amount of tile would be 300# or so on each wall; I was thinking of fastening them directly to the sheetrock with Liquid Nails.
What do you all think?
Thanks, Mac

[mannymanbo2]

I would be concerned that the weight on the wall with 24" studs would cause it to bow.
On either wall, the wall board could pull off or even break.
At least screw the wall board to the studs first.
I would over lay the wall board with plywood if I were you.