String spacing (pole position) or size: Bridge wider than Neck
Wire length: Neck longer than Bridge
Resistance: Bridge higher than Neck
It could be any/all/none of the above. The wire colours seem to get swapped around in different kits at different times, so you can't always rely on one colour being for a particular position. Compare what you can from the above list, and if you still can't decide which is which just install them anyway... it's easy enough to swap the positions once you hear how they sound.
Thanks Guys
come to think of it, one was a bit tighter for the scratch plate when I was test fitting them. I might do a resistance just to see what the outputs are.
Joe, please check the thread / video's on the bridge set-up. There is an element called compensation that usually means that the measurement from 12th Fret to Saddles is longer than the measurement from nut to 12th fret. You do not want to drill your post holes and find that the saddles will not screw out far enough to get your guitar intonated.
Joe - may want to check your length from the brige and nut to the 12th fret - regardless of the overall scale length, these need to be the same. As Gav's indicated, check the How to's on setting the bridge location and building your guitar for some detail on how / what to do.
This is what I have from the nut (messured from the fretboad side of the nut to 12th is 43.3cm
12th to saddles is 43.5ish cm
12th to bridge edge is 46cm. Dose this look ok?
Joe - start measuring from the 1cm mark (or another easy to find point). Tape measures are great for bulk measurements (walls, etc) where you've got a bit of tolerance, but for guitar building, I'd skip the chrome end bit as it may be adding a mm or three depending on how it is sitting. If you start from say the 1cm mark, you may be a bit more successful. The two measurements you are looking for is from the centre of the 12th fret each way - to the nut and to the centre of the saddle. I'd also go as close to the E string's path as possible and do it as well for the G string - as my grandfather once said - measure twice and cut once. In this case - drill once. Give those a crack and update this thread and we should be cooking with gas.
Thanks Brendan, I have a 1 meter metal ruler somewhere I might use that instead. I will get the measurement with the ruler and let you know the length I get.