Chocolate milk stout advice please

I’ve brewed any stout let alone a milk stout.
Here’s what I’m thinking…

8# golden promise
2# chocolate wheat
1# caraviene
10oz pale chocolate
3oz roast
1# lactose in the boil.

If I mash at 150 and use irush ale yeast
first gold @ 60
Fuggles @ 20
1oz of each.

Looks okay to me… I might mash a little higher to help with the thick mouth feel & sweet taste that I would anticipate from the name. Maybe 154F? I wouldn’t want it to be thin. Cheers!!!

Isn’t the lactose unfermentable? Wont that give me a good body n full mouth feel?