Yes that is it. I used the method in your 2nd link for the interim but the line manager is much easier.
We use this little gadget in place of leaving our lines attached since my wife and I have one bar each over 5 kites. Using this method eliminates the need to run your lines, which decreases time spent rigging and space needed to rig. In the cold spring and fall it certainly makes things a bit more bearable.
Basically the way this works is like this starting from derigging to rigging....
1. coming in, wrap your lines and lay them downwind of the kite. take each line off the kite and put them into the line manager in the order you removed them.
2. finish wrapping your lines being careful not to allow the manager to invert on your lines
3. pack your kite
Going back out (rigging)
1. pump your kite,
2. unwind a few meters of line downwind of your kite.
3. attach one line at a time to the kite as normal but in the order they are kept in the line keeper.. being careful not to turn around or twist the lines... orientation is key.
4. Take the bar around to the front of the kite passing the lines underneath the leading edge
5. Flip the kite, all the lines should now be laying on the top of the underside of the kite
6. walk out to the water with the kite and either ask for someone to hold your kite or drift launch.
if you are careful this works every time... I have had to come back in and fix shit twice because nobody is perfect and I may have twisted the lines or turned around or something... but 2 out of a over a hundred launches is pretty reasonable considering the benefits of taking no more space then your kite... you no longer need 30m of beach, and speed... you flip your kite and hand it to someone at the waters edge... you walk into the water and launch. no tangles, no weeds in your lines, no sticks etc......
This is one more step then leaving lines attached but we only need one bar each which reduces the cost quite a bit....