Can anyone advise whether the rig allows the effective flagging out to front line on Naish Park system?

It will allow it to flag, but the 5th line will be in your shot all the time. I never got the point of those 5th line kites. All my kites flag very well to the front lines.

Cool. It's the 4-line Park im referring to anyway.

What about the stoppers/ plugs that come with the line mounts? Do these have to be left off (one side at least), to enable the safe use of the front line flagging line?

Might just be overkill. Just received the mounts at the shop and got to try them out just before the wind died, but was still very impressed.

On a 13m crossbow in about 10mph.

Also just to mention, with the Cabrinha system I did not try to activate it, but with the ids system that flags on both front lines the camera shouldn't affect the safety system but can't talk for sure.

https://vimeo.com/56607619

It doesn't.

Should affect a non-loaded 5th line. I wouldn't want to risk a single front line but it's worth a shot.

Finally got out with the Roam2 and the Stringy line mount.

Yes, VERY nice to have the lens rotated 90˚ and get a "full frame" shot when parked'n'riding.

And can confirm the mount is so stable that the raw footage (apart from being upside down!) is very watchable

This is the new line mount video shot last week.

http://youtu.be/7Q_fBM6WnHg

Anyone have issues with looping the kite? Would be really scary to get a line caught mid kiteloop, which was an issue with the older model for me.

I've seen this and experienced it but can say its more rare than you think.
one of the ways to resolve this was to prevent the rear lines from being able to snag on the mount. I did this by producing the mount plugs. this virtually eliminates the possibility of the rear line snagging on the mount.
if you are concerned with the mount snagging, position it as close to the rider as possible.
keep an eye on where your lines twist and avoid this area for camera position.

That's my latest prototype child:

Works cool so enjoy copy it, improve it etc.
GoPro HO was not interested in it