I have been running many blogs on Wordpress and I have upgraded wordpress a lot of times. So I hope to complete your task within 1 hour at max.
Some of my blogs which are running on Wordpress are:
It is too easy work for me and i can do this within 10 minutes. Currently running three wordpress website and can do it easily.
You may take a look the sites following:
[login to view URL]
[login to view URL]Mais