Hey Sebol
I hate to break it to you but you are going to need a much smaller kite than 12m to kite the winter Nor' westers.

A typical reasonable day is a quite gusty 15-25 knots NW then strong rain squall of up to 35 knots and then a lull of down to 10-15 knots after the squall, then back to 15-25 knots again until the next squal.
An unreasonable but truly awesome day in winter is gusty 30 knots with showers and then gusts up to and over 40 knots in rain squalls dropping back to 15-18 after the rain. Biggest jumps guaranteed if you can control your kite in the squalls also massive often violent secondary lift in jumps

The Nor' westers are quite predictable once you know what you are looking for in regards to weather patterns. You MUST keep an eye on the advancing clouds and rain upwind of where you are riding. My advice is to get the hell away from land at the approach of crazy squalls and be ready to flag your kite if you are within 100m of the beach. You will be much safer teabagging at zenith 600m to 1km from shore rather than it hitting when you are near the beach, thats when sh1t happens!
Squalls generally only last 10-20 minutes at the most, but watch out for the lull behind the rain once the front passes through. I don't recommend wild winter kiting for learners, but once you have a bit of experience and are feeling confident, winter can be absolutely prime time

I have a bunch of specials on my site if you are looking for some cheap smaller kites to "do" winter safely.
I love winter kiting!

Good winds,