I was on a strict time-schedule, as i would do several banners and ingress-event that day. I took the tram 18/19 to "holtet" and walked from there. The start was quite slow, and I started to doubt i would be able to finish the banner within time. My estimate for this banner was 3h 15min. After the first 5-6 missions it started to get faster.
The park with all the statues are really nice. At one place there was even a natural "fog-machine" that was spectacular! And you will get a really nice view of Oslo.
I managed to do this in about 2 hours and 20 minutes, both my feet and I would have liked to spend more time in that park.