The 4-way jib system seems too complicated and invasive. Here is how I will set it up. Please call it Andinista Jib System..

What boat is the 4-way system on? It not often used on spinnaker boats.

I have a couple of comments on your system.

1) From the picture, it does not allow fore and aft adjustment of the leads. This is important in going upwind.

2) That is a lot of load on a V jam type cleat

3) When you adjust one lead, the other seems to go in the opposite direction

A simpler system was used on the Tornado. It had 4 or 5 loops of line protruding from the tramp. The jib blocks had a quick release that allowed you to easily move them to the appropriate loop. On the Tornado there was also a barber-hauler. to adjust the jib.

Nacra 5.5, no spinnaker for now, it has tracks for fore and aft adjustment.
Leads will move in opposite directions and if set up centered, will maitain equal distance to each hull.
I don't like the idea of attaching the jib blocks to loops on the tramp. Never tried it but I'm not considering to take it out for that anyway.

The "Andinista jib system" ended up working perfectly. It can be adjusted fore and aft and in-out quite easily. The blocks move symetrically in and out, keeping the same distance to the hulls. With a decent line it doesn't stretch a lot. You really forget about it once set up.
I tested it a couple weeks ago. I didn't take any picture but it appears on a feew milliseconds of this video, (1:00 and 2:45). I used two lines because I didn't have a longer one, therefore the two colors.
http://youtu.be/uilA3tq3_Pw
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