If you live in Canada, i guess that means that you'll actually see winter temps/ice/snow
, thus you may actually care about grip & ground clearance, at least during winter season.
For clearance .. if you are not against redoing alignment, i'd rise her back for winter. Yes, at expense of worse acceleration due much bigger diameter and much duller steering due very high profile sidewalls you can get some of your mentioned "<very> lowering" back, but it doesn't seem best possible choice, especially because staying low won't do anything with shortened shock travel. Better more "normal" tire sizes but not herra-low. Maximum diameter wise on stock wheels/suspension 225/55/17 rubs, 225/50/17
was fine. Of course that won't give you info even for starting point to think of clearance/flushness, due having non standard camber & lowering.
For actual grip, on snow/ice, imho better to go as narrow tire as possible, due our cars being relatively light. BTW, smaller wheel tires also cost less. So how about getting 16x7
Sparco Terra instead of those 17x7.5 Trofeos?
Rally looks as free bonus.
And fit some very recently released hakkapeliitas 9 205/55/R16 on those if studded are allowed, or hakkas R2 / Blizzak WS80 / Michelin X-Ice Xi3, if studless?
I myself also have track-ish camber (-3F,-2.5R), but leaving it as is even in winter (though of course less camber would enhance contact patch in winter, due tire never having as much flex prior grip-loss, as on summer tarmac). But it's simpler for me ground clearance wise, as i'm still having suspension at stock height (but even then at some situations in winter i wished for a bit more clearance).
P.S.
Sorry about saying NOTHING in post about offset/flushness that you asked, but imho in winter one should rather care about grip to not crash, instead of looks, quickly covered with salted dirty snow at that.