The Drifter does not have the wind range like the SBs and flys smaller than the SBs. I think the 7Drifter flys more like the 6 SB. So I would think that would be a pretty big jump from a 10 SB to the 7 Drifter. IMO the 8m SB would give you a lot more range. I am not familar with the 7 SB, but I would still see that as a better choice than the 7 Drifter. I have the 10SB, 8SB, and the 7 Drifter. When it is too much on the 10SB then I am on the 8SB, but I doubt I could ride the 7 Drifter. When I am blown off the 8SB then I am on the 7. You did not say your weight so it makes it a little hard to determine. The 7 Drifter is a great kite if you live in Maui or Cetral California coast where you would ride it a lot in the right conditions. For Toronto and the East Coast I think you would get a lot more out of the 8 SB or possibly the 7 SB.
I was considering the drifter for 30+ knots when other guys are riding 5 & 6 kites. In ontario we get very gusty conditions in those winds and large swells 2 to 3m. Also thought it would be decent for the snowkiting. Im 75kg. Thanks for your info.