Personally I'd do Duchess then Gnut, for the added survivability before worrying about damage.  As for books that's a tougher call.  I think I'd focus on Artak then Duchess, them Gnut but their really isn't a bad wa to go.

I'd probably use the books on Duchess. You want her A2 booked especially. Once you get the A2 booked you can use the rest on others.

I'd probably vote Duchess first, for leveling.

Ok, thanks

Hi, I don't want to make a new topic. I am thinking about artifact sets for Gnut and considering Relentless set or Savage set. What do you think? I will probably make better stats with Savage set.

I would think that Dutchess helps you everywhere in the game and has more versitility. 

A good source for these kind of answer is also the website of Hellhades or ayumi . There are tons of videons on youtube about most of the better champs...

Don't worry about sets. Focus on making sure the items have the right stats.