I'm sorry, but you don't want to do that, that bit of the build guide is wrong. Set the high E saddle fairly far forwards, so there's only a bit of adjustment screw poking out from the threaded hole in the rear of the saddle into the centre hollow.
When you get to the intonation adjustment, the saddles will move backwards from the nominal scale length position, the low E more than the high E. If you set the saddles in the mid-position, you then have limited scope for moving the saddles back before the saddle springs are fully compressed and you can't move them back any more.
And measure the scale length from the fretboard face by the high E string slot to just behind the front edge of the high E saddle, the point where the string will leave the saddle. This is normally around 1mm back from the front edge because of the curce of the slot.
You really want to fit the neck and the two E tuners, then run string down to the bridge so that you can align the bridge centrally, with both bits of string equal distance from the edge of the board. Mark the position of teh sides of the bridge with pencil or tape, and then measure the scale length with the bridge in the central position.