Dry Hopping my IBA - Need suggestions

So I just got my DFH Indian Brown Ale kegged and carbed but I think I'm going to want to dry hop it.

I've never dry hopped in the keg before so I need some suggestions.

So can I dry hop with pellets or should I stick with whole leaf? I'll be using a bag.

If I can use pellet, let me know what you think would be best to use. Here's what I have on hand (all pellet). If one of these doesn't work, what would be a good addition?
Cascade
Columbus
Chinook
N. Brewer
Hersbrucker
Kent Goldings

DFH IBA RECIPE:
10oz British amber malt
10oz Crystal 60L
8oz Chocolate light malt
2oz roasted barley
12 Lbs 2-row

Single Infusion - 150* 60 min.

1/2oz Warrior Hops for 60 Minutes
8oz Dark Brown sugar at 10 minutes
1oz Vanguard Hops at Flameout

Wyeast 1187

Finished up at 1.017 - forgot to take hydro reading until it was in the keg so it's a tad sweeter than I wanted but what are you going to do eh?

I dry hop with pellets in the keg. I either put in a bag or in a large s.s.tea ball with weight added. In either case the bag and the tea ball are attached to the lid with a length of ss.chain or in the case of the bag, plain dental floss that reaches just shy of the bottom of the keg. Has always worked great and when the flavor is right I can easily remove the hops. If you have anymore of the Warrior or Vanguard those would be my choice.
mark
Beer Diary...

I've dry hopped with pellets plenty of times and it always comes out great.... I always forget to use a hop bag though.