Hi all. I'm intending to book 4 tickets LHR < > BOS this summer using Avios and a couple of BA Amex companion vouchers, probably travelling Premium Economy out and Business back. This will be my first Avios redemption. Is there anything I should be looking out for to ensure we get best value?

It appears the route is served by a mix of 747s and 777s - is there much difference between them?

TIA