- I could be wrong but I think the arrow keys move 0.25 in space (someone correct me if that isn't true) so move it 4 times if you want to move it by 1
- I think it varies depending on the mesh, so I don't know off the top of my head sorry
- the only way I think is looking into the text file that is the model, but then you cant easily distinguish the vertices apart
- the model coordinates only relate in whatever way you use them, if you have a 1x1 plane and apply a 64x64 pixel texture to it, and then a 128x128 pixel texture, the first will just look more zoomed in if that makes sense? the bigger the texture, the more it gets 'squashed' to fit the face of a model you're applying it to (I recommend just messing with them to see how it works :) )
Hope any of this helped haha