I think your question is totally reasonable. Somewhere back in the day, there was talk of different width inserts for different tires on Hummer wheels. When I contacted TWF (many years ago), they said it's all the same insert, they just run the impact down as far as it will go on any tire. Theoretically if you had a super fat bead, the o-ring between sections wouldn't seal, but nobody is talking about that. My very limited experience is OZ radials, Bias TSLs and 2 flavors of radial TSLs on the same wheels/inserts and everything worked fine.
I did have problems with one PVC insert that left the tire leaking and discovered it was cut narrower than the other 4 I bought. TWF seemed to not believe me and was not willing to give me any credit or help on a proper width insert, but that 3/8" was all the difference between working fine and the tire spinning on the rim at low PSI.