League of Legends (LoL) Question: Optimal Build for Bard?

I run:

9 AD marks, health/armor seals, mr blues and armor quints.
0/9/21 masteries.
Q max, W second, E third, ultimate whenever possible.
Starting with Q or W depending on how fast ADC can shove. Leaning towards Q most of the time though.

Items: Frostfang (Possibly coin, I tried it a couple of times), Sightstone Mikael's Blessing, Randuin's Omen/ Frozen Heart, Locket of the Iron Solari.

ADC with wave clear / ability to dodge is decent. Sivir should do fine for example, Caitlyn too but I guess you kinda want to win lane as Caitlyn instead of keep up with the opponents laner. Maybe Lucian/ Graves too.

My guide goes through all that and more, http://www.mobafire.com/league-of-legends/build/6-4-between-a-rock-and-a-bard-place-in-depth-guide-448143

> What runes would he use? I run a very AP heavy runepage. MPen Reds, AP Yellows, 6 AP / 3 MR blues, and AP Quints ( or Move Speed. )
> What masteries? I run 21/9 to help his roaming and trades.
> Which skill leveled first? Q is mandatory. The CDR and Slow duration is something that you really need.
> What items? I build him for kiting and peeling. Frost Queens, Mobos, Rylai's, Twin Shadows, Sightstone, and Morellos
> Which ADCs would be able to solo lane without him? Sivir and Graves are the two I see are able to do it. I think it's more or less a matter of supports. If you're against Leona, you CAN'T roam without risking your ADC dying. However, if you're against Sona or Janna, and they play passive, you can roam freely.

• 9 marks of hybrid penetration, 9 seals of health, 9 glyphs of magic resist, 3 Quintessences of armor.
  
• 0/9/21 masteries.
  
• Max the Q first, then the W. E is maxed last and of course put a point into the ultimate everytime you can.
  
• talisman of ascension, Ruby Sightstone, Mikael's Blessing, Ohmwrecker, Locket of the Iron Solari, Mobility Boots.
  
• Caitlyn, Corki, Ezreal, Graves, Lucian, Quinn, Sivir, Tristana, Vayne.
  

I would say that maxing his Cosmic Binding is mandatory. He's a great roamer and uses Spellthief's Edge very well. I'd say that you want to play with burst-oriented ad carries who have a strong all in or poke based ones. Champions who scale into the late game well but are weak early aren't very strong with Bard since he'll need to roam in the laning phase and you want an ad carry that can solo the lane without him like stated previously. (This means a strong laning phase, waveclear and range.) So Caitlyn is ideal.

I'd say hybrid penetration marks. Health/Armour Seals. Magic Resist Glyphs and 1 AP/2 armour quintessences are optimal. I'd start W if you want to place a few health packs around your teams jungle to help your jungle out and then recall for mana. But otherwise start Cosmic Binding.