I think you'll end up with the same loss of years in life, possibly more loss given far fewer rates with F which means, as you noted, you'll end up in J and therefore the problem of finding seats remains the same. If you do for the F option I would be looking to maximise that as much as possible by focusing your cities where F is served. Remember a number of oneworld airlines don't even have F. Even Qatar only offers true F on its A380s and the only upside of F on its short-haul is access to Al Safwa. I'd be aiming to make it a true round the world itinerary (which, just to be clear again, this award does not require) to get the most value.I've been planning on booking a OWA 280K fare in J for some time now... however, reading these posts, it seems like a *lot* of work and has potential to shave years off of ones life to align everything.
I'm wondering - are the OWA 420K F fares easier to book? Is there more availability? Is it worth spending the extra 140k points for the added convenience and *some* legs in F - assuming not all routes would have F carriage available.... and thus would be relegated to J for those anyway?