Back again
First things first, thank you very much for your replies. As suspected, and referenced before, the measuring thing parallel to neck axis versus parallel to outer strings was just a bug in my brain, cause the difference is almost none, but your answers cleared any doubts that I had on the subject.
Regarding the block thing in AutoCAD, well, I sorry again for thinking everyone knows AutoCAD... in AutoCAD, a BLOCK is a container of things, it can have lots of different uses, and lots of different properties. In this situation, this is a static block with the drawing of the bridge, nut and 26 (I think, could be more) frets, correctly positioned for the original scale length (can't remember, but that doesn't matter). Because it is a block, when one scales it, everything inside scales in the same proportion, so If the original scale length is, lets say, 25 inches from nut to bridge and I need a 28 inches scale length, all I have to do is to scale the length of this block and all the frets will be precisely positioned. So with this one block I can do any scale length without the need to use ever again a fret calculator spreadsheet or that link above mentioned. Scaling a block in AutoCAD is as simple as change its properties or use the scale command with numerical input or previously drawn reference for click input. No need to import anything from any file. I can do Mandolin or Bass guitar scale lengths with the simplicity of a few clicks, just need the scale length drawn. Drawing the frets is another task that will require to draw or copy each line to each place, but that is peanuts... I use AutoCAD because I know how to use it properly, I've been an Civil Engineering Draftsman for quite some time now, working on Dams, Bridges and some roads. From there to guitar drawing/design is just pure joy... If anyone needs some AutoCAD boost, ring me a bell...
@SwedishLuthier, that photo cleared all my thougths. How is it to sand the graphite to the final neck shape compared to sanding wood? I once sanded down some metal fillings done to a defretted guitar (to replace the removed frets), and that was weird. Very interesting and nice approach there.
Regarding the perpendicular fret, curtisa, this last reply is GOLD, thank you very much, so precious and detailed info there that I have never thought about and makes so much sense... again, thank you very very much.