I want to buy myself a cheap used sail around 4.7. But I don't want to have to buy a new mast or boom. Due to being quite heavy and strong, the wind has to be over 40knots for me to be out of control on my 5.3m so would love a cheap smaller sail for those rare crazy days. I worked out that with my 160-210 boom and 430 mast I can just barely go down to a 4.7 if it has an adjustable head.
I know ezzy has them, can you name some other brands to look out for?
Thanks
In a 4.7m size, most of them.
Generally only wavesails have adjustable heads, and only once you get below about 5m. KA is around 5m, Gaastra is around 4.5m, Pryde is around 3.9m... very few slalom sails have them.
Loft sails are interesting - they recommend a specific size, then allow the next shorter and longer sizes. The only way for longer masts to work, is with an adjustable head.
A 5.3 in 40 Knots! That's hard core 
I'm usually looking at a 4.2 or smaller when it's a solid 30 Knots.
You can tell when it's solid 30+ as there are no kites around!
Ezzy 4.7m recommends a 430 mast as an altertnate to 400. Boom is around 170. There is plenty of adjustment in the head, and the 430 rigs ok.
I also have a 4.2 KA Kaos which seems to have a stupid large amount spare strap at the head, I am tipping the bigger sizes will be the same.
I have used a 4.2 Kaos on a 430 and you can get by with it but it's obviously much better on a shorter mast. 4.7 Kaos or Kult is fine though on a 430.
Andrew at KA may have an older one , I know he still has a few 06-07-08 sails around. He is away for a couple of weeks but when he is back you should give him a yell.
Excellent info guys, much appreciated. Yeah I realise it would alter the performance slightly due to different flex but I think I would be just glad to be able to get out in those crazy winds without ripping my arms off whenever I unhook, so anything is an improvement.
I understand where you are coming from... I recently picked up a *new* 2000 era 3.7m sail... best value ever!
