I haven't investigated this option but as long as the dimensions will allow I don't see why it wouldn't work. Just need to be sure it will physically fit or you may have to make some adapters or supports but no biggie. I believe it comes with supports to span out to the main rails. Let us know if you try it.
Don’t know about the IW 650 but I just got the GMG pizza oven and it fits perfectly in the IW 885. Only had a week, one of boys cooked a couple pizzas. He put stuff on ‘em I won’t eat but they were a hit with his brothers and friends.
Check out pizza stones at The Ceramic Grill Store. My buddy Tom Vogds has the largest assortment of sizes. Give him a call and he'll steer you the right one. He sells GMG stuff too. Tell him the GrillMeister sent ya.
Using Ceramic Stones as Pizza and Deflector Stones In Ceramic Grills, we use ceramic stones as pizza stones and heat deflectors. As pizza stones, they absorb and radiant heat to help cook the pizza dough evenly. It's best to push the pizza stone into the grill's dome. In the dome, it's easier to...