Background
Using a KA Kaos three sail quiver in 2011/12 models. Bought them second hand. Owned and tried a number of different 5-batten recent wave sails. Much prefer these. Have used each of the 5.3, 4.7 and 4.2 sizes more than a handful of times. Mostly sailed them in small wave conditions.
Tuning
In my experience found that in their ideal wind ranges they are best tuned as follows:
1. Use a constant curve 400/19 ICMS mast (I have an Ezzy Wave Carbon RDM, although the 4.2 recommended mast is a 370)
2. Down haul so that the second batten from bottom overlaps mast 1/4 of the way (easier to judge than looking at looseness between battens at of top leach - the material is quite stiff)
3. Use upper eyelet (you loose power and "feeling" in their wind range otherwise)
4. Outhaul about 5-7 cm depending on how strong the wind is
The 4.7 has an adjustable head (contrary to web site). This is and 4.2 is set with about 10 cms of extended mast (measured to inside of turban).
Batten tension can play an important part to how a sail sets. However these appear to be tensioned correctly when I got them and have not had to adjust. (Found that other sails can respond well to successively more tension in bottom battens than top ones to promote shape and twist.)
Characteristics
In summary the Kaos sails are very efficient for their size yet go neutral very quickly.
They have a good range and can be set fuller with less down haul and outhaul in underpowered conditions. Have also used the 4.2 much overpowered with another 5cm more downhaul and outhaul - the sail still setting well.
They are not the lightest sail but never felt that weight was an issue even as a welter weight sailor. Maybe schlogging would be less tiring or carrying the gear to the beach
?
Also found the KA Kaos easier to waterstart than some other makes (with same boom length). Not exactly sure why but could be that some of don't allow the water to run off as easily. This is of course dependent on technique plus the state of the sea, wind strength and size of board.
Built
Very solid with X-Ply/kevlar throughout and lots of reinforcements. Think they are going to last a long time. The weakest area is probably the mast pocket with one showing some reef rash. Another has a harness hook indent but it's not going to rip.
Have only seen one other post with Kaos tuning suggestions - "don't over downhaul them" and apply "neutral outhaul". However, with neutral downhaul it makes the sail feel less connected/responsive to trimming - for me.
If you have any other combinations of settings that work for you, respond to this thread.
I've had the 2007 Kaos's 5.7, 5.3 and 4.7 since new and they are pretty much the same as yours are except they only have the one clew position.
I set mine on a 430 RDM (really need to get a 400 for the 4.7 but it works fine with the adjustable head - a little "stiff" feeling sometimes 
) and usually set them with just a little twist at the second batten for a bit more power to twisted off to the middle of the luff for overpowered. The outhaul works for me with about an inch of positive to a bit more when overpowered.
They haven't had heavy work in big waves very often but except for a harness hook dent they are pretty much as good as new.... no plans to change them in the near future.
I'm more than happy with them 
