Hi Stray,
You should consider getting a 5m kite for those conditions. It also really depends what you want to do in those winds i.e. your preferred style of kiting ?
Pro's who compete for big air will go out on 9m kites in as much as 45 knots. Personally at 85kg I find that on a Twin tip, a 7m kite is a great size for up to 35-40 knots for boosting big airs. Yes that would be slightly overpowered, but when boosting big airs, that is what you need.
When on a surfboard in more than 25 knots, a 5m kite works best for me.
With a good technique you could easily fly a 3m or 4m kite in anything at or above 30 knots. Here is a 3.5m in about 30 knots:

So, if you are not looking at boosting big airs and just cruise around, then a 5m kite (or less) would work best for you in 30 knots +.
If you want to try boosting with a 5m kite you may find it difficult at first as they are very fast and landings can be pretty tricky with less hangtime.
You also want check you line tuning and make sure your kite isn't oversheeting which would make a big difference in strong winds.
Christian