if your lax-lhr flights will be in y why dont you just do lax-jfk-lhr or lax-ord-lhr.
you will earn more miles, you will be able to do the lax-ord or lax-jfk in j or f via electronic upgrades plus you will have more options of flights as lax-lhr is 1x a day and it leaves at night and you arrive in lhr rather late in the afternoon, whereas you can do an early morning lax-jfk and an early evening jfk lhr and arrive in lhr early in the morning ready for work thats what i do