I have been on this configuration a half dozen times already on EWR-LHR runs. I would suggest (in business) an odd numbered F seat and a sequentially one number higher even L seat (e.g. 3F and 4L). This is because the row numbers are misaligned between the center and window sections (presumably to keep the straight seats as all odd numbers) and these seats will be close together directly across the aisle.

As another note, this configuration usually flies the 6pm EWR-LHR followed by the 7:55am LHR-EWR return. They do only sell 30 business seats and I have been able to stand by without any issues onto these flights in business when originally booking flights later in the day even when these flights are “sold out” in business. Pretty much everyone gets upgraded and even non revs have an easy time getting business (unless the whole plane is oversold due to the drop in economy seats on the swap forcing operational upgrades) with about half the flights I have been on going out with empty seats in business.