As the big bike is at work today I measured the tyres with some calipers:
Trail King 2.2 Protection 27.5
Carcass = 59.6mm (2.34″)
Tread = 54.0mm (2.13″)
Magic Mary 2.35 Super Gravity 27.5
Carcass = 59.8mm (2.35″)
Tread = 61.9mm (2.44″)
That’s on Flow EX rims at ~25 psi.
I’ve only ever used the UST Rubber Queens (they’re currently on the 26″ hardtail) and Protection Trail Kings, never the basic unreinforced carcasses, which I’m sceptical would hold up well under hard cornering without a very wide rim and higher than ideal pressures. Never run them with tubes either!
Personally I think the RQ/TK 2.2 UST/Protection is almost the perfect rear tyre if you something that rolls fast-ish, brakes and drives brilliantly, corners well and is never snappy and handles all ground conditions decently. When it’s loose (be that mud or dry) I prefer something with bigger edge knobs up front but it works great when I’m riding well, just doesn’t tolerate poor technique (lack of lean) because the centre knobs don’t really do turning.