When the surfers start to see kiters, riding surfboards in surf like they do, but using the kite just as an extension to give them extra speed and pop their attitudes will change dramatically, Mauricio Abreu's a perfect example - But imagine what Kelly Slater would be able to do on a surfboard if we teach him to fly a kite?

I think the key is personal preference, what ever you feel comfortable with....do you prefer to ride unhooked more than hooked? You can ride hooked in no problems in the surf if you like to ride that way.
As for shorter lines i havent tried them yet, i want to try 18meter length, i've heard you get more speed, faster kite response, easier to relauch because the kite is closer to you, more upwind ability, and when you want to jump you just pull back and your in the air, a lot faster than with standard lines. But it takes a bit of gettin used to and i hear if your used to 27meter and you switch to 18meter it will scare the hell out of you....(but after a day you should be used to the shorter lines)
As for the 5th line its great, however if you crash the kite in the waves badly the 5th line can rip the kite in half.
For your first time in the waves, just go out in real small surf so you dont get into trouble.

I agree don't change your usual setup at first, it's best to change one factor at a time. You wanna be comfortable with your setup so you can concentrate on the waves.

It's amazing how much fun 2ft surf can be with a kite in the mix... well maybe I'm soft but I think so anyway! Big surf (5-6ft is big on my scale) scares the hell out of me.. but in a good way.

Practise up your toeside riding, it's handy for waves. Also you'll find when you're heading out it helps a lot if you carve into oncoming waves at the last second, try to hit them at 90 degrees or close, not too fast, keeping the kite and the nose of the board high. Hopefully this should stop the waves washing your board out from under you. Head out on the underpowered side too, and be pretty conservative to start with, try to keep the kite in the air and your feet in the straps.. it can be much harder getting either back where they belong in the surf. Try to avoid the temptation to send it when you see the first big ramp rolling towards you

I'm no expert but that's what I've discovered so far, hope it helps..
Dave

I would try keeping your kite low through your turns on the waves or else you will be picked up as you swing it back and wont hold your rail