I'd just add here to what @
KARFA said on the upgrades, Are you planning to buy an IB or BA ticket (different to the operating carrier) or a combination? This will help us advise.
If you are buying an IB ticket, IB just did a huge promotion that
may mean award availability gets very tight in around a week, particularly on US routes. I don't know the ins and outs of IB upgrades, but this certainly won't help.