Another extremely happy BWS Party owner here. I have not got around to extending the charcoal pan to hold more fuel, hasnt been an issue to spend the time on it. I have had 8+ hours before with briquettes, and with the heat diverter the water lasts about as long. We started competing this year and have been using only lump. The way our schedule is at comps I dont over pack it, and get about 4 hours between loads, but thats the way I like it.
I tried the stoker years ago when I first got the party, and frankly I didnt care for it. The product worked as described, but the Party didnt need it and it was more a bother than anything. Im a tech geek, but once the novelty wore off, it was just a chore to setup and take down. I can dial my Party into my 240 - 250 zone with both eyes closed and half asleep.
If we ever upgrade to a bigger smoker, it will be another BWS. The fatboy your looking at has the same cooking space as the party, just configured differently. I chose the Party over the fatboy because of the weight, and now that we started competing im glad i did. Get whatever configuration suits you better.
50+ lbs of brisket, could of done 2 more.