I’m lucky enough that my A4 printer can print starting at 3mm from each edge of the paper, so for me it works perfectly when I set the following margins:
left: 0.5cm, top:0,5cm, right: 0 and bottom: 0 (why 0? because we have the 1cm for gluing anyway so the dotted line will be printed and the Grid for positioning as well because it’s far enough from the edge).
I’ve made a quick graphic, using your .vit and .val, to show what’s interesting (sorry for my poor graphic skills haha):
Until now, the Layout margins (or previously known as fields) were used as well for the margins of the tiled pdf. The tiled pdf will get its own margins margin, see the following dialog:
The tiled pdf margins needs to be set so that the printer can actually print the content (in my case they should be > 0.3mm, except for right and bottom).
Where do you suggest to do that? We can’t know the value because it will be different for each printer. What we could do is add a warning/help message somewhere in the dialog, to explain what the margin values are for.
You mentioned printing on letter sized paper. For now the tiled pdf is only exported in A4 (I’m about to change that, see the dialog). Could that explain why you have issues with scaling?
I’ve had trouble opening your .val file, because it hat the valentina version 0.6.3. Do you know were you got this version from? because now we have 0.6.0. There was also a tag “previewCalculation” in the val file, that the programm doesn’t know.