Firefly tank

[motto (RIP)]

In answer to your question about the possibility of requiring major adjustment after new track has worked a bit David, I don't believe so. From what I know of Sherman track the links or blocks were articulated using pins set in rubber, there was nothing to wear as the relative movement was allowed for by the flexing of the rubber.
The really clever part is that the links or blocks are set at a slight angle to their neighbours so as the track wants to roll itself up. To flatten it out flexes the rubber in one direction while going around a sprocket or return roller flexes it in the opposite direction from its null position. It's what is referred to as a 'live' track.
That's the track that I'm familiar with anyhow. I expect Sherman track all worked on the same principle but may be wrong about that. This type of linkage is still in use today on the M113 track and no doubt others.

David