They are both orchestra seats. K is 3 rows up, but the seat is further to the side, while N is slightly more center. Would you rather be three rows closer and four seats farther over or three rows farther back and only six seats in from the aisle?
I've never had a problem sitting farther over, but if your friend has never seen teh show, I would perhaps suggest more center. The show is a big show and I've never heard about anyone complaining about sitting in even the last row.
"Less Of A Marilyn, More Of A Jackie"
www.richardhblake.com