Congrats on achieving Elite status and good luck with your upgrade. I'm not sure which routes have the best chance for an upgrade. If you want *A all the way, you are probably routing through Frankfurt, which should (I think) be OK at that time of year for upgrading (depends on day of week, etc.).

As an alternate for your consideration, why don't you fly YWG-YYZ-ZRH and then take the train to Basel. The train only takes about 1 1/4 hours and there are several per hour (one of which does not require a change of trains). This will likely get you where you want to go a lot faster than flying from somewhere in Europe to BSL.

Rumour has it that YYZ-ZRH-DEL may be an early recipient of the upgraded 763 - if so, that would be another bonus although I suspect if true, word will quickly circulate and every FF will try to route through ZRH reducing your chance of being able to use your SWU