Going from my wild uneducated guess (Wikipedia) it looks like about 5 years... and potentially 1 artist. Then again they lived on a solitary island doing nothing else, apart from the occasional shelter from viking raids.
Again, yes a chance would be great. Not familiar with the Guttenberg outside of it's first printed status. Are there pictures and illumination or just quality text ?
There were little dudes on horseback riding around the pages, and fantastic borders. The Huntington in LA has a copy and they change the pages every now and then.