If you’re going to go with a Weber, definitely get the 22" model if you can. Also, I would recommend NOT buying the "Silver" model if you can find the "Gold". The main difference is the enclosed ash basket — I kick myself for not having this on those windy days!
FWIW, there is plenty of room for an 8-10 lb shoulder on the 22", and enough room to add coals near the handles on the grate, even without purchasing the hinged model. No doubt the hinged grate would be more convenient, but it is certainly not necessary.