i was going to do extract since i dont have a large pot
This is the recipe I came up with to make this a partial mash. Again this is just my 2 cents, your the brewer so do what you feel
http://hopville.com/recipe/283040/oatmeal-stout-recipes/oatmeal-stout
This is what I came up with to help make this a more balanced recipe.
I got rid of the dark lme and replaced it with 2lbs 4oz of light dry malt extract. The reason why was with dark malt extracts you dont know what percentage of what grains are used to achieve the color which may or may not make your beer great. Also by using a lighter extract you get to play
around with the grains a bit more to balance the beer out a bit.
Your going to need some 2 row barley or any other base grain to convert the flaked oats. I chose 2 row cause thats pretty much what I use all the time.
Also I lowered your roasted barley down to 4oz, and added 2oz of black patent. Both are very simular in color and when overused can add to a dry astringent taste in the beer, I like using a combo of them both.
Now on to the mash, put all the grain in the grain bag and make sure it is loose enough so the grains can be stirred around and dont clump together. You have around 4.5 lbs of grain, if we use 1.25qts of water per pound of grain we are looking at a little under 1.5 gallons of water. Since your trying to keep the boil down lets leave it at 1 gallons of water. Heat this water up to 157 degrees, add your grain bag and stir for 2-5 minutes, your looking for a temp of around 154 degrees for 60 minutes. Put the lid on and walk away. In a seperate pot you want to heat up another1.5 gallons of water to 170 degrees. Remove the grain bag from the pot and let it drain. Then place the grain bag in a colander and slowly pour the 170 degree water over the grain bag allowing it to rinse of any additional sugars. This will give you roughly 2 :rockin::rockin:gallons of water due to some absorbtion of water to the grain. Add the dry malt extract and then bring it to a boil, add your hops, chill, top off with water to bring it up to 5 gallons, and pitch your yeast.
if youve never done a partial mash it sounds complicated but its really not, and its great prep for when you go all grain.
check out deathbrewers :rockin:stovetop partial mash method, he has a picture tutorial in there to help answer any questions and take the fear out of the method.
Good luck, hope the beer turns out well.
P.s. for the record i wasnt trying to make this more difficult, you could always stay with your current values and just lower the extract a bit and add at least 1 lb of 2 row to convert the flaked outs. Again Best of luck