Double Sweet Stout

Trying a high ABV double sweet stout. It's just above the Foreign Extra Stout Style classification. The recipe is a "kitchen sink" of grains, below. Suggestions?

Ingredients
0.5 Carapils
2.0 lb Maris otter
8 lbs Light Liquid Malt Extract
0.5 lbs Munich Wheat Malt
0.25 lbs British Black Patent
1.0 lbs Chocolate Malt
0.5 lbs 60L
0.5 lbs 15L
0.5 lbs Roasted Barley (300L)
1 lbs Barley Flaked
2 lbs Oats Flaked
0.4 oz Magnum 60 minutes.
0.50 oz Fuggle 15 minutes.
0.50 oz Goldings 1 minutes.
Yeast: S-04

OG: 1.08
FG: 1.015
30.1 IBU
ABV: 8.5-9.0%

What kind of mash are you doing (temp, length, BIAB vs mash tun, expected efficiency)? Also, is it a full boil? You may want to up the bittering addition to balance that massive grain bill. Maybe up to 1 oz of magnum. I would drop the carapils too if you want to get the FG down to 1.015. You have about 6% cara-malts from the crystal and the extract is gonna have carapils in it already. You may also want to mash a little lower to counter the high amount of unfermentables in the extract.

I will soak the grains over night in warm water to dissolve oat sugars. The plan was to conduct a 3-step BIAB mash, 110* & 140* & 155*, for 20, 30, & 30 minutes. I'm thinking about 65% conversion efficiency.

Yes full boil for an hour.

I added the extra Carapils and flaked barley to create head retention with 2 lbs of oats.

Good thoughts on hops. Thanks.