CL5 & SL6 are not leather grip, I think the grip is metal tube with leather pattern, plus paint job, it feels completely solid. Some dealers maybe or maybe not intentionally used misleading descriptions, but Zebra official never said so, they describe it as screen printing.
LT3, SL6, TF12, they have the same size. (Their caps are actually interchangeable with the first gen sharbo)
(ST3, ST5, AL5, SC5, CL5, LC5 are of another type)
TS10 used to have a slightly lighter model, SB21-A, 19.4g, aluminum body, other TS10 are brass body. It’s discontinued now, SB21-B, SB21-C are still available. My complaint about TS10 (and GS40th) is the plastic thread and a sticky rotation feeling. I know maybe Zebra thinks their executive model need a steady tone, but I’m just not happy with the result. It will stuck if you try to rotate it quickly, I disassemble it, and add some grease to improve it to a usable level.
As for the selection of materials in some parts, what happens is completely confusing:
Full metal body: LT3, SL6, CB8, TF12, SW15 (star war limited edition, based on CB8)
Plastic connector in the middle (the first few also have plastic tail cap and thread): ST3, ST5, AL5, CL5, SC5, LC5, TS10, and even their top price model, 20k yen, GS40th, is still palstic thread.

So the material here has nothing to do with the price. A 3k LT3 with metal, 20k top model with plastic, huh. Like Zebra never really thought about it, or at least not for those earnest collectors. (meanwhile, still launched anniversary model GS40th?)
Normally they are the same. In my experience, for vintage sharbo, if it looks okay, most of the time it works as good as new.
For TF12, I got one for 4k yen, its market price is around 6k, which is a reasonable price I think. Overall I love it, it does have a sense of luxury.
Except for the problem you mentioned, another is that despite Zebra uses promotional words such as “ultra precision, high skill” on it, the fact is that it’s just okay level. There are visible burrs on the edges of each lattice, and it does make the touch slightly worse.
Upper rod and the grip of TF12, somehow the upper part looks nice while the grip is sick.