Apologies for the buzzwords, but I'm trying to weigh the most optimized method of of travelling from YYZ-SIN-YYZ in consideration of the following:

Upgrade-ability - I am AC*E and have 25 eupgrade credits. Route optimization to make best use of my credits for the round trip (ie most miles with my butt in J). My ticket will be in Y, but presumable T+ . Likelyhood of upgrades vs paid J vs SEs upgrading also needs to be considered

Comfortability - I understand Asian carriers have a better soft product in Y. How should I hedge my bet / allocate legs in Y assuming that at best, 25 credits will only get me part of one way in J. And with which carrier?

Thoughts and input are welcome