AP Mid Gragas- Build Optimization and Advice?

Hi /r/LeagueofLegendsMeta ,

I'm currently a level 30 AP Mid player looking to start ranked. Very comfortable with playing Kassadin, Morgana, and Ryze, but I'm looking to add Gragas for some fun and variety.

Sadly, Gragas is underplayed. Most guides are outdated or inefficient, so I'm looking for advice from any Gragas/AP mids here.

Currently:

• Boots, health pot3
• 3x Doran's Ring
• Deathcap
• Sorc shoes, Void Staff, Rylai

Get blue whenever possible.

Max Q and E first, but take 1 level of W at level 2 for sustain.

I have about 5000 IP saved up to buy T3 runes. I already have flat armor and flat AD. I'm thinking MPen, possibly mana regen or CDR.

Gragas seems to scale extremely well with CDR. The effects of blue buff on his cooldowns are very noticeable. For that reason, I'm thinking about adding a Morello's after deathcap.

In lane I poke and farm with Q and use W+pots for awesome sustain. E+flash allows me to escape most ganks with ease. At 6 I try to gank a sideline, and then back for Dorans and blue. Teamfights I stay back and spam Q and use R when needed.

Any thoughts on my build? I'd love to hear some of your opinions.