I am currently planning a mini-RTW, YUL-SYD being the main required trip, in Y. I do have enough points to do it in J, but would rather save those points for further travel. Luxury is nice sometimes, but generally I've never been one to need luxury and always prefer to sacrifice a bit of luxury to get more of what I'm buying (in this case, travel for my points). I expect some discomfort and fatigue definitely, but I don't expect it to be intolerable... but then again, I'm not 6'5 200+ lbs etc, which I expect would make a difference??
I'm focusing on LX, TK, SQ, and have UA in there on the return. Have never flown UA though, now a little worried based on comments, might have to see if there's another option but LAX-YUL I don't think so? (other than AC with scamcharges)
I've received good info and help here, and actually haven't received any "don't fly in Y" comments - everyone knows it's not going to be high comfort (and who knows, I may live to regret it).