HKT seems to be the best bet for turnaround.
For the outbound portion:
You could do a routing like this. I strongly recommend doing LX YUL-ZRH and not LH YUL-MUC. It is very easy to find seats on that LX route.
Then you could do CDG-BKK (also quite easy to find seats) on the 77W with suites.
Finally you could do BKK-HKT.
http://www.gcmap.com/mapui?P=YUL-ZRH...T&MS=wls&DU=mi