29 inch is about 74 cm. You will need the largest locker.

I use this Japanese site for coin locker information:
http://coinlockersearch.com/shinjyuku3.html
http://coinlockersearch.com/kamata.html

At 3chome, only locations #2 and #6 have the largest locker size at 500 jpy per calendar day.
At Kamata, all 3 locker locations have the largest locker size at 500 to 600 jpy per calendar day.