My company has me flying from LHR to the US East Coast. My options are either the non-stop on BA in WT+ or on AA with a connection in Y. I am an EXP on AA and blue on BA (w/ 100k avios).

The ideal situation would be to fly on BA in WT+ and upgrade with avios. The flight is wide open in J (maybe 20% full), but there is no availability right now to upgrade.

On AA the flights are wide open and I'm pretty sure an EVIP would clear.

The ticket would be booked through our corporate travel office.

My questions are:

1) Reading through the wiki if I change my address from the US to the UK (corporate travel is in the UK) can I still upgrade with avios? I understand from the Wiki you have to have your Avios address be in the same country as the travel agency.

2) Is there any better way to monitor for upgrade seat availability than checking the BA website multiple times a day?

3) What have people's experiences been on seats opening up for upgrade? On AA it seems they'll upgrade people as long as there is an empty seat in J whereas this isn't the case on BA. I'd say the chances of the upgrade clearing are better on AA.

As a general rant, while the ticket is not the most expensive, but it is in full fare WT+ or Y. It seems BA's upgrade strategy is much more of a headache which has me leaning towards AA right now.