Still waiting on the motor but for the wiki with the newer arm like I have, the correct rear blade is the A configuration. Picked up a 14" A blade - which nets to a 4" difference than the OE.

Cannot do 16", as smigen past the end of the blade towards the mount, the arm curves. The longer blade will work...just won't look good.

The E70 blade is 15"....compared to the stock OE of 18" on the E53
I suppose the curve of the arm does make up for 1"