255x85r16 on 16x8 with -10 offset ??

I wouldn't get caught up on tire weight. Lighter tires will have less rubber but look the same, they might ride slightly softer but will be less durable to the unexpected events that cut tires off road. Do the 285's outperform the 255's? I suggest doing the research on skinny tires ;-) There are several other options other than the Cooper's or Toyo's, I've had both of these, they're just a different tire, they both drive well, I ran them on my Jeep and my Tacoma. I currently run 255 Falken Wildpeaks. On road they’re better than both if the above, off road probably not, especially in deeper slick stuff, the Toyo’s liked that more