Welcome to FT. I've asked a MOD to more this to the Lufthansa forum. Most of the major airlines have their own information forums here.
The A343 used often on this route,which could change, has the 2-3-2 setup. Since there are 2 of you I'd take either of the 4 or 5 AC HK seatings. At 1.86 meters you're over the general comfort zone for most airlines even in economy but in PE you should be comfortable. I personally would go with Row 5 as it seems the legroom in the bulkhead of this setup doesn't come with substantially more room and the tv will be wall mounted. But that's just me.

http://www.seatguru.com/airlines/Luf...340-300_V3.php