Preparation of Ikea billy hack

Few days before I move to west. List of things that I will need to sort out ASAP.

Bought Ikea Billy bookcase x 2 - Replacing the idea of hiring someone to custom made wardrobe for that little space, taking account into how many pairs of shoes I have, I give up.

http://www.melanielissackinteriors.com/blog/2016/4/26/robs-library-wall-ikea-hack

After reading the link above - how to turn a bunch of Billy bookcases into a build in wardrobe. Even though the colours have been altered heavily on this photo. I believed those Billies in real life must be a great pleasant to look at. 

There are many DIY's steps involved. Like using decorative moulding and duropolymer coving are something I have never come across in my DIY's journey. At the moment I am considering whether should I get a nail gun or follow the original steps by using a no nail glue. (or both? maybe) 

Please not to forget I have to paint them as well!!

To-do list below

1) Zinsser shellac primer (widely recommended by worldwide bloggers)/Dulux Multi-Surface Primer & Undercoat (the primer this blog has recommended)
2) Gold spray paint (yayy goold! Wilko Metallic Spray Paint Gold 400ml has good reviews and just £3.95!!!)
3) Dark blue paint (Farrow & Ball's 'Stiffkey Blue' or Abigail Ahern's 'Bowery Blue') Recommended from the blog as well, however my billies are already painted in dark blue, probably these won't be matching them and I have to look for a new one...)
4) Decorative moulding and Duropolymer coving (please, stick to simple design)

Optional
5) nail gun/no nail glue
6) brush (was thinking to get a spray gun. It will create an even coverage beautifully however I read from another blog if I stick to oil base paint there should not have the problem of creating brush strokes)

Oh man...Good luck to me.