You gorra decide where you wanna start to fish/expect to catch on the whip.
Down the inside shelf? In the track?
When you've decided which rig is most suitable for the venue - 4 or 5 mtr, start plumbing up 'to hand',
Once you've clocked the 'line' of your float, to assist, you could also temporarily add sections 5m to 7m so you've got the tip of the whip 'over' the float to 'exact' things up and also check out the canal bed contour as the float moves through the swim
A load easier to show you on the towpath than to describe.........
![cheesy :D](./images/smilies/YaBBSmilies/Smilies/cheesy.gif)