Whats the significance of the distance between the harness straps where they attach to the boom ??
I have seem some people with them almost together whilst others are a good 30cm apart !!!!
The instructional dvd Beginner to Winner said to put them together.
There doesn't seem to be any advantage to spreading them wide, but I can think of a possible disadvantage. Wide would perhaps encourage the rig to rotate around the harness hook rather than the centre of pull in the sail when you are sheeting in/ easing out.
So I have them together now, though I started with them wide.
In "the olden days" harness lines were miles apart because the centre of effort of the sail could wander all over the place. People would also have their hands well apart on the boom too to be ablke to counteract the huge twisting forces of the sail.
With modern rigs the COE is much more locked in (Stiffer masts, sail twist etc), so it is easier to zero the harnessline on the appropriate location to best counteract the drive of the sail.
Having them close together gives the sailor better feel for sail trim. The harness line takes care of the lateral pull, leaving hands for the fine tuning.
Luxury, sheer luxury
JB
for ppl doing flat water blasting or speed sailing/ formula/ slalom ppl would ushally have the line further arpart because it is easier to retain power in the sail, and you dont need to use your arms asmuch, but for sailing in waves. freestyle etc you will see more ppl with close lines because it gives more responce from the sail, it is faster and easier to de-power the sail while still keeping the sail balanced, me personally use lines around the harness hook width apart because i like the feeling knowing what the rig is doing and being able to get that little bit more power by sheeting in while being able to depower easy, but i think it all really comes down the personal choice
Once you go narrow you won't go back :P I run mine about 70mm apart (centre to centre). Running them narrow also gives you much lower wear on your harness lines.
I sail with mine together. When you try it, give it a couple of sessions and you will never go back. It gives you a much better feel for the sail and wind.
Only disadvantage is that mine have now twisted a little and sometimes grab a hold of me in a gybe.
close together for sure! feels so much more balanced and more in control. looks like we all agree on something!!! 
As close together as possible, I dont have any space separating my lines at all. I even thought about geting the old school kite harness lines which only had one attacment point.
