I tend to value BAEC:AY+ at slightly below 3:1 as much of my redemptions are ex-HEL and much higher for OW redempitions, so in your case I'd say BAEC.
But for their Gold you'll need 4 BA flights (code+metal, AFAIK). If you don't have those, you'll stay blue, no matter what. It's easy to do it (CPH-LHR-anywhere UK return) but an extra chore if you don't have BA flights normally.
OTOH, AY+ is something you know inside out
BA upgrades:
"Upgrade on British Airways, Iberia and American Airlines flights.
The formula is:
Avios for the cabin you wish to upgrade to - Avios for the cabin you make your booking in = Avios required to upgrade one way
Here's an example for a peak one-way upgrade from London to New York, upgrading from premium economy (World Traveller Plus) to business (Club World):
Club World: 60,000 Avios - World Traveller Plus: 40,000 Avios = 20,000 Avios to upgrade
To work it out, you can use our reward flight calculator or we'll work it out for you when you're ready to book your upgrade."
http://www.britishairways.com/en-gb/...g-avios--index
WTP is their eco+ Golds have extra reward availability.
Can't comment on the others.