Just my .02 cents on this matter ... loads may look great, but this flight is often weight restricted from what I've experienced. I've non-revved the flight quite a bit & often will do the hop up to SFO first as SFO loads are lighter most of the time & it doesn't seem to be as weight restricted. Something to keep in mind even for those times when pax loads still make it look good for ZEDers, etc. I hope you make it!
As for the Y seats being hard to sit in after 45 minutes ... unless you've been absolutely spoiled with First Class seats your entire life, it's not bad at all. I've done the LAX-SYD-LAX flight many of times on both the 747 of UA & A380 of Qantas & never found it difficult. But I've also never been that picky I guess. Fly safe.