Your tile gauge should be 100mm approx. - that means a 100mm exposure of the tile and a 165mm cover by the tile above.
Your full tile will be 265mm in length. Tops and eaves tiles are shorter.
Tops tiles typically need a double batten because they are an overcourse.
Eaves tiles sometimes also need a double batten as they are an undercourse.
If you have the top battens wrong you possibly also have the bottom/eaves battens wrong - you possibly have the whole roof batten gauge set out wrong?
Your full tile will be 265mm in length. Tops and eaves tiles are shorter.
Tops tiles typically need a double batten because they are an overcourse.
Eaves tiles sometimes also need a double batten as they are an undercourse.
If you have the top battens wrong you possibly also have the bottom/eaves battens wrong - you possibly have the whole roof batten gauge set out wrong?