Increasing ABV with grains

I am going to make chocolate oatmeal stout using BCS's McQuaker's Oatmeal Stout recipe as my base. This recipe has a target ABV of 5%, and I want to up to 6.5-7%. I don't think adding sugar is a good idea because it will dry out the beer, not desirable in the oatmeal stout.

I increased all of the grains by pretty much the same percentage and then adjusted some manually to keep the same SRM, IBUs. See attached. Is there a rule of thumb when adjusting a recipe in this manner?

Then for the chocolate addition, I was thinking cocoa powder: 4 oz in the boil, 4 oz in the secondary, both dissolved into boiled water or some alcohol. I know this issue is covered to exhaustion in the forums, but I'd appreciate your 2 cents considering the recipe.

Thanks all!

 

To maintain the original recipe, upping all the grains and maintaining their original percentages of the recipe is the best bet. A lot of time I just up the base malt but that changes the recipe.

 

Thank you BKnifefight