Thank you for your comments, and particularly for the observation regarding the J seats. For some reason I was under the impression that the seatwells on the 747-8i were slightly bigger in the non-bulkhead rows - but apparently not. If that is the case, I'll probably go with MUC and the 2hr connection. We are on the UD of the 747-8i for our outbound flight.
The seatwells are significantly larger on the 748 downstairs, middle seats. Most spacious C seats of any LH plane.