I assume you're meaning to cut leg quarters in two, but I've never had anywhere close to that on mine. (More like only a couple 10lb bags of leg quarters.) I'm not sure how many you can fit or how long it will take being so full, but I'd use wing/drumstick racks on the top grate, and add a middle grate for another grate's worth of thighs. Still, 150 pieces is a lot of chicken. Whatever you do, let the chicken sit out a bit to lose it's chill, protect the cooker from the wind best you can, and start with at least a chimney's worth of lit. Hopefully you'll get better and more experienced chicken smoking feedback than mine, though!