Never found it an issue and still don't. I'm only 6ft and play a Sonor Phonic Plus 22" BD with the square toms, and basically the same tom mount design.
It'll have a c1mm rolled and welded shell. I've got a SY1406, which is the 6 inch deep version. Beautiful drums but not worth as much as the Ferro-Mang steel or beech/birch wood Signature drums.
Only a couple of bits, the main hardware differs, it's just some random bits. Worth noting as well that the original Yamaha Power V kit with the rubber bits on the tom mount and BD spurs is actually an APK in a slightly different frock and one inch shallower toms.
There are some interesting Yamaha bits on Premier kits of the era. The 3000/4000 cymbal stands are a good example of this. They're Yamaha cymbal stands but with Premier specific legs. The bottom assembly of APK/XPK/Projector etc of that period bass drum spur is also shared with the Yamaha 8000...
They are the originals, they look like Yamaha ones as they first appeared when Yamaha owned Premier. A lot (though by no means all) of the kit hardware was derived from Yamaha stuff.