I will soon be eligible for a BA companion ticket, from the qualifying spend on my AMEX card. This will be the first time I have received a companion ticket and also the first time that I want to make a reward booking using my miles.

I have just over 55k BA miles , and once I receive my companion ticket it is my intention to use them to get me and the other half some flights from London to NYC. I am a little unsure what would be the most efficient way to use my miles.

I was under the impression that using the miles for economy tickets might not be the best way to spend them, due to taxes, surcharges etc.
I had a plan of buying two economy tickets and then using the miles to upgrade to business class, but I don't know whether the companion ticket allows me to upgrade Mrs Moose?

Please could someone help me gain a better understanding of the companion ticket and reward flights, I am also open to any other options I have which may be a better use of the rewards.

Thanks in advance.