Sailed a 7.1m and 5.0m today,wind around 15-22 knots.
The 7.1m KA race felt a handful,the 5m felt right in the gusts but overall way too small.
If i rig anything bigger than my 6.3m Warp in above 15knots the sheer weight and size of sail reduce my performance.
For me 7.0m is a big sail.
> 5.2m 
Case in point, today I sailed my 5.9 and although it's an incredibly light sail ('12 S1) compared to say a 5.2 of the same vein it feels mcmassive, this makes freestyle etc that bit more difficult 
Because that's what I enjoy though I always try and sail as small as possible so my sense of sail size is somewhat warped. Often i'm out on a 4.7 and sailing around on my 100L freestyle board while people are still sailing 7+m sails...horses for courses and all that. It's all about perspective.
A big sail only feels big when there's no wind or there's to much wind.
Depends on wind strength and size of the rider.
Performance related to sail size, IMO is sometimes a bit cack handed
I can get mid to high 20's on my 9.5m, yes I can go a hell of a lot faster on my 5.8m, but if the wind isn't there then the 9.5 will destroy the 5.8.
I think the ratio of wind speed vs board speed is also in favor of larger sails and lighter winds.
but then I'm a fat lazy basket so I need the bigger kit
+1 Elmo. A sail feels right and light when chosen for the right range.
In gusty winds though (15-to-22), you can't win - there will always be times when it feels heavy, under- or over.
Was it offshore in Perth to be so gusty ?
How much sail you can handle in a given wind also depends on board size/type and your own weight. For example,
On my formula board (100cm wide) I can handle an 10m sail in winds from 8kts to 18kts. Over 18kts I'm way overpowered and need to drop down to a smaller 9m sail. Heavier riders would be on 12m sails dropping down to 11's.
In the same wind strength 12-18kts I can also comfortably handle my 7m sail on a medium sized slalom board. Above 18kts or so I change down to a 6.2m sail on the same board.
Im not a wave sailor but Id guess that the same principle would apply and sail sizes for a given wind range would be smaller again as the board size/type is different.
+ another for Elmo's comment. I've had my 5.6 feel heavy at times in marginal winds, then gone out on another day when the wind was a consistent 15kts with my 7.5 and it felt light.
When I started w/surfing, the shop that I bought the gear off sold me a 7.5 cammed sail as my first sail (which is also the sail I learned to waterstart with)...so no sail is 'big' imo.
I used to think over 5.7m was bit and hated having to use the big heavy 6.6m..now I've got a 100% carbon mast I reckon I could use a 8.5m.
The rig is so much lighter!
Agree with everyone else re right sail for wind..That's the bit I find hard..
if you get used to a big sail it will no longer will feel big
i've been on my 11.0 alot the last month or so and have gotten very comfy on it, i've sorted out the heli tacks but struggling with duck jybes
now everything below is easy even the 10.0 feels small, light and easy to throw around
when i got back on the 5.0 in the storm last week i was nearly in shock
Any sail bigger than my 6.3m Warp for me feels big,heavy and slow in comparison.
I can get nearly as much topend out of my 6.3 as my 5.7,but if i go to 7 or 7.8 i bottom out at around 27/28knots.
I tried the 7m Reflex 3 and feel was similiar to KA race,big,heavy and rigid.Starting to think in my old age i need to use a free ride sail in the bigger sizes.
Other problem i find is my 69cm wide 111 litre Fanatic Falcon sits too low in the water with 7m plus sized sails,especially when sailing out against the swell and chop.With my 6.3m it does the opposite,sitting very high out of the water.
Used the KA 7.1m the previous day for first time,wind was around 10-14 knots. Rigged it with much less downhaul and outhaul on my bigger 75cm wide mini formula board and was surprised i was planing most of the time.Going to keep it for the 10-15 wind range.
Bottom line,if you weigh less than 70kg and wind is 15-22 knots,a 5.5 to 6.5 should be plenty.
Petermac - stop smoking it
As everyone has posted the idea of big sails is a relative concept (to a number of variables including the ones you mentioned)
1. The idea that a 5.5 -6.5 is fine in 15-22knots for a 70kg sailor, is something I would have believed 17 years ago when I was a 70 kg Swan river sailor and sails had narrow wind ranges.Modern sails have massive wind ranges when rigged correctly
2. A Reflex 3 7.0 felt big heavy and rigid - what horse@*%t - If you had rigged it poorly maybe - all sails when rigged poorly will feel heavy as they dont breathe - but this little sucker - yes little - breathes like a dragon
3. As most sail designers will tell you downhaul ranges are minimal - outhaul is what you use to trim the sail
Can I suggestPeter - dont worry about the chemtrails - get the correct masts - rig sails as close to spec - dont complain about the wind - At least in the west you have some
RANT OVER
Petermac, Maybe a full blown Race sail like the KaRace or Reflex is overkill for you. You are most likely better off trying a Koncept or Overdrive, physically lighter, a bit softer in feel and easier to pump and easier through the transitions.
Just a suggestion.
