Chocolate Milk Stout partial mash, seeking feedback

Planing on brewing a chocolate milk stout next Saturday and am trying to finalize the recipe. This is what I have so far:

3.3 lbs Special Dark LME (or Traditional Dark LME)
3.3 lbs Golden Light LME
8 oz Lactose
8 oz Maltodextrin
16 oz Chocolate Malt
12 oz Carmel 120L
4 oz Roasted Barley

.5 oz Magnum 60 min
.5 oz Cluster 10 min

Steep specialty grains @ 152 for 30 minutes (Or do I need to actually mash the grains for an hour?)
Start boil w/ 6 gallons
Add all LME, lactose and malto
Boil for 60 minutes

Any thoughts/suggestions are greatly appreciated. I'm looking for a somewhat sweet, chocolate-y stout with little coffee and caramel notes and a very smooth finish.

 

looks good, may be a little heavy bodied for my taste because of the malto, lactose and high lovibond specs grains. Steeping them will be fine as none of them will convert in a mash anyway. What is the alpha percentage on the Magnum?

 

I would suggest changing the chocolate malt to 1/2lb and adding a 1/2lb of pale chocolate malt. This will increase the depth of the chocolate tones. I say tones because it's been my experience that unless you add a couple tablespoons of good quality baking chocolate to the boil it's difficult to get a deep chocolate flavor with malts alone.

 

+1. And leave out the malto. Too sweet.

 

@FastAndy - Alpha on US Magnum is 14.7%

My LHBS doesn't stock pale chocolate malt. Here's my slightly changed recipe. Thoughts?

3.3 lbs Special Dark LME (or Traditional Dark LME)
3.3 lbs Golden Light LME
8 oz Lactose
8 oz Chocolate Malt
12 oz Carmel 120L
4 oz Roasted Barley
4oz Cacao nibs

.5 oz Magnum (US) 60 min
.5 oz Cluster 10 min

Steep chocolate, carmel and barley malt @ 152 for 25 minutes
Start boil w/ 6 gallons
Add all LME & lactose
Boil for 60 minutes

Safale S-04 yeast
4 oz cacao nibs in secondary