Milk Stout Recipe Suggestions

Hello fellow homebrewers. I've been brewing now for about 2.5 years but always using others recipes. I've taken a Milk Stout recipe and made some changes to it to accommodate my inventory and what I think would be good. I've listed the ingredients below. I would appreciate any recommendations.

(Partial Mash)
2 lbs 2-Row Pale
3 lbs Maris Otter
10 oz Chocolate Malt
9 oz Crystal 60
8 oz Black Patent
8 oz Flaked Oats
1 lb Lactose
1.4 lb DME (late addition)
1.5 oz Cascade (60 min)

My calculations show this coming in with an initial gravity of 1.058 and 31 IBUs.

Also, what mash temp do you think I should use? I was thinking of around 68C (154F) for a some added body but with the oats and lactose I didn't think I needed to go to full-body mash temps.

Thanks ahead of time for everyone's thoughts.

Gotta have some roasted barley. It's a man law as well as a beer law!