Yes, I agree 10 Bft is a lot of wind, no question. To measure wind, I use an analog Deuta hand-held anemometer (precision 0.5 m/s or 1 knot), possibly at 2 m height above water level and away from any nearby interference (rocks, trees, fences, building, etc...). When measuring 35-45 knots, 35 is lull, 40 average and 45 is peak on the beach, but usually, it's a bit more windy at the middle of the lake (3-5 km wide). Beware of reading calibration as well, a cheap digital hand-held anemometer gave 48 knots peak and an online wheather station was topping off at 30 knots about 1 km downwind from the beach.
We have these kind of gale wind once a year in October or November, so I want to try that with say a 2.3 or 2.8 sail. When I tried it with a 3.0 sail last time, I got a leach to my back footstrap because as Ola pointed out, equipment is literally blown away from me when I fall, so it can become scary at time. However, if drifted away by the wind, one can always go back to shore on a lake (i.e., visit some private properties). November is fine because water is not too cold yet, i.e., 9-11°C, but air can be 4-6°C and the main trouble is to keep fingers warm enough on the boom despite the wind chill factor. January or February is way too cold, ice builds up on the sail, so better go skiing...