Economy or PE to UC with miles

I am just too lazy to do it and I am sure it someone has already worked this out.

Which is better value, buying an econaomy or premium ticket if you want to use miles to upgrade to UC?

I travel to the west coast, LA or SFO, quite often and would ideally do PE during the day and UC at night.

[preiffer]

Buy an L Class - 40k miles gets you to PE on the day sector and Upper on the night. Shouldn't cost you more than £500 in cash.

[Scrooge]

you may want to think about doing that the other way around,the night flight goes by pretty quickly,but the day flight just goes on forever and having the suite to relax in is a nice thing and seeing as you are gold you still get entry into the lounges/CH .